Sunday, April 30, 2006 

vectors - b.o.b

i thought this unit went by pretty fast. yes i did. soooo....i thought this unit was tough. its so confusing like im not quite sure how to figure out triangles when theres lotsa triangles in the problem that you have to solve for...it gets really crowded and confusing. so thats what i have been trying to really focus and study on mostly.




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scribe

So on friday we only had one class and it was shortened because we had an assembly. Mr K was explaining to us how we could become millionaires if we saved a certain amount of money from our paycheques every pay day. He showed us with the TVM Solver on our calculators. On the TI-83's we press the Apps button, choose the finance menu and then choose the TVM Solver.

this is what you should get on your screen.

N = number of deposits [month]
I% = annual interest rate as a percent
PV = principal or starting value [opening balance]
PMT = payment [negative value for investments]
FV = future value
P/Y = number of payments per year
C/Y = number of compounding periods per year

after you enter in all the known values you have, highlight the value you want to find then press Alpha solve.

unfortunately i dont have my calculator with me so i cant show you guys step by step what we did to make us millionaires, but i will definately post it up as soon as i get it back.

tomorrows scribe will be jason.




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(>O_o)> .:Blogging on blogging:. <(o_O<)

I found that this unit is in the middle of easy and hard. The easy part of this unit is when your drawing a diagram and solving the triangle using our calculator, and the difficult part of this unit is when your putting angels. We have to be careful on were we put it because on this unit it is very easy make mistakes, for example, you didn't put the right angle were it should go, then your answer would be wrong because of that mistake. I think that a little notes about the angle thing would help us a lot, Well for me that would help because I think that I might forget it.




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BOB "VECTORS"

This unit is kinda hard because in order to to solve some triangles problems we need to have a basic skills on trigonometri which maybe some of us have forgot those stuff,, because we learned it when we were grade 10 or grade 11, but anyway it's a good thing to remember again those things. I never thought those triangle problems and solutions can be applied to a more realistic types of problems like the problems that we did in this unit. The only things that maybe I need to work on is figuring out the right diagram for the word problems and proper labeling of side lenghts and angles, in that way it would be much easier to solve the question that asking......




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Saturday, April 29, 2006 

Blogging on Blogging (Vectors - Ivy)

all right..... what do i know about vectors...well....you know about the angels, it makes me confuse.... but i figure it out someway. well hopefully...i don't know if im going to do good in this unit..but i need.to do good..or else i'm not going to get my credit.... i know i did bad in probability and statistics...i didn't really go look on my note or review so it's my fault...and i am working fulltime in the evening.. but anyways.. well.. problem is in this case..... in grade 10 i didn't understand trigonometry the sohcahtoa thing or the cosinlaw i don't even know how the heck i passed that course..but anyways....i've been looking through my notes and i was trying to understand it...and i actually did get it..i just need to take more time to look on my notes.. and hopefully i'll pass.




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Friday, April 28, 2006 

BOB Post

Hey kids,

I enjoyed the vectors unit. The only thing i was confused about was the laws of complimentary angles, etc. I couldn't remember this from last year so i had some trouble with that. other than that, the biggest problem was making sure i got the angles right, and the length of the lines. other than that, i had fun with the vectors unit. I liked it mostly because I had just finished that unit in my physics class.

thanks,

Nik # 1/2

... WE'RE NUMBER HALF!
WE'RE NUMBER HALF!!!




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Thursday, April 27, 2006 

BOB on Vectors

To me this chapter seemed little short. so far we had no notes on this chapter, and i gues we are not going to have one, as we began a new chapter "Personal finance". i had some difficulties on Vectors chapter. the hard part was getting the rigth shape i.e. the drawing of the triangle. if you lose control of this step, then your whole work is completely nothing. so i got to do practice on getting the right stuff. then i gues the math part will be lot easier. hopefully things will go as predictated. thats all folks.




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Blogging on Blogging

i found this unit pretty easy, but i had a problem with how to figure out the angles and if you don't know how to figure out the angles you are in trouble. But Dom show me easy way to do it thanks man. Most of the classes i was a way even Mr. K told me that he's little bit worrying about me if i understand the material, but i guess i'm doing fine so far.
good luck everyone.




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Wednesday, April 26, 2006 

BOB - Vectors

I just want to say that this unit was somewhat hard and somewhat easy. Everything that we did so far seemed quite easy. Especially if you took Physics. By far, the biggest problem I had was figuring out the angles. Plus, I find that it's very easy to make mistakes when doing the problem solving. Either because you're not reading the problem carefully or you somehow get the directions mixed up. Hopefully I won't make those mistakes during the test. Well, that's all I have to say . . . later.




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The Crazy-Inflatable arm-flailing tube-man's Scribe

Hey Kids,


Sorry the scribe is a little late. But here was the Day:

We've Started a new unit: Personal Finance. For this unit, you will need both a Thinkfree.com account, and an Irows.com account. today, we worked on page 154 in our texts. the unit thus far is a reiteration of what we did in grade 11 personal finance, however we will be doing everything over the internet, using spreadsheets. I suggest you review how to use Excel spreadsheets, using page 154 for tomorrows class. This unit will be done mostly with Spreadsheets, so you will need to have an inane understanding of precisely how to use a spreadsheet. We had some trouble saving our stuff to thinkfree office, so it is highly recommended you register to Irows.com tonight, as you will be unable to do this through the school computers. your thinkfree account should also be up and running. KNOW YOUR PASSWORDS. This is critical. Many people forgot their passwords and got nothing done. If you'd like to get anything done tomorrow, it comes highly recommended by doctors and pharmacists that you do this.


We WILL be in the Computer lab every day this week and next. Hope you know how to use an Imac!!!

P.S. Tomorrows scribe will be..... RUBIE!





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Blogging on Blogging

This unit went very fast...

I think I have an all right understanding of this unit (I've been mistaken in the past!), though I must say, I'm really glad it's over. I'm not too fond of vectors at all. :P There are a few things I might struggle with tomorrow, but with some study hopefully I'll nip that in the butt. I am fairly comfortable with the drawings, I just have to remember to factor certain things in to what I'm drawing.

Good luck everyone, I hope you guys do well. :)




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Vectors

Well here's my little blog on this unit for vectors. Althought Mr. K said that everything kind of goes downhhill after statistics, I was kind of surprised at how much I actually struggled with this unit. I don't know what it was about the unit. At first I had problems drawing the diagrams asked. But after I overcame that, I started having trouble with the entire problem. Like I mean, for some reason, I just couldn't interpret what I was being asked. But as we did more and more problems, it became better. Here are the key things that I needed to remember. When drawing the diagrams, make sure you draw them big, because it can become quite confusing, and not to mention messy and this is what can cause you to get the incorrect answer. Another thing about drawing the diagrams is to know exactly in what direction it's going. What I mean, is that you should know and familiarize yourself with the 5 ways that you can write directions.

For example:
N40° E is 40 degrees to the right of the North.
65° S of W = 65 degrees going downward from West.

So I guess I just wasn't used to the directions and such. Another useful thing you should do is labelling all the angles in the diagram even if you don't use it. It's just a good habit of doing that so that you don't miss any important information you might need. Other than that, everything else was pretty straight forward. Luckily, I managed to become somewhat comfortable with doing these problems before the pre-test. Hopefully I can keep it up for the test :P




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Tuesday, April 25, 2006 

pre-test day!!!

well, nothing really happened today, just had our pre-test. which i found, pretty tough and confusing for me. so i cant really explain any of the questions here..because i dont get them myself. sorry!! soo all i can say is just review all our past homework and remember all those formulas and stuffs....and im sure, the test will be a piece of cake...oh i wish!! wish i had something else to write about, what a waste of a scribepost. ahhh. kay well, good luck everyone on studin' and on the test! k, later!!

-corrie

* oh, and tomorrow's scribe will be Nik # 1/2




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HEY EVERYONE!

just wanted to let you guys know ahead of time that todays scribepost won't be up anytime soon...but it will be up, just late. sorry guys, all because of work! k, later!

- corrie




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Monday, April 24, 2006 

Scribe

Just so you know, I was caught by surprise and didn't know that I was suppose to be the scribe for today since I didn't read the last scribe post. Luckily not much happened today so I'll give a brief description of what happened in class.

In the morning, Mr. K talked about a new site for us to use. The URL is am40s.pbwiki.com. Next he put us into groups to work on a problem with multiple vectors. We just use the COSINE LAW or the SOLVETRI program on our calculators to solve the problem. Some had trouble with the problem and Mr. K decided not to take in the group assignment so we all worked on the problem together.

In the afternoon, we continued to finish solving the problem since we ran out of time in the morning and then we had a homework test. Then he assigned us some questions to do in the textbook for homework.

HOMEWORK: p. 341, #1-9 (I don't think we have to do #1 since it seems more like an experiment.)

NEXT SCRIBE: Corrie




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Sunday, April 23, 2006 

The DaVinci Code Quest Sunday



It started last week. Google releases one puzzle each day for 24 days until the movie "The Da Vinci Code" is released in May. So far 7 puzzles have been released. You have to solve the puzzle to reveal a clue. Then you have to answer the clue question(s) to advance to the next puzzle. You can win a prize for solving all 24 puzzles. Now I realize this is all about marketing and they're really just trying to get as many of us as possible to go see the movie but the puzzles are really cool! Google searching often helps to find the answers. One of the puzzle questions can be answered using The Fundamental Principle of Counting and the very first (sudoku-like) puzzle uses a couple of mathematical symbols.

Challenge 1: What is the question that can be solved using The Fundamental Principle of Counting and how do you use the counting principle to find the answer?

Challenge 2: What mathematical symbol is used in the very first puzzle and what number does it represent? (Not the "delta," in a later puzzle it has a different meaning.)

You have to sign up for a Google Homepage in order to play, but that's a free and very useful service. After that you can begin the game. Click on the US button to start 24 days of fun! (Actually, 17 because you could work through the first eight today.) Don't forget to also find the answers to the Challenge Questions above!. ;-)




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Saturday, April 22, 2006 

Solving Vector with given 3 magnitudes.

Hi guys sorry for the delay,,, Mr. Kuropatwa introduced a new type of problem in vector which is kind of harder than the other problems.. But still we can use the parallelogram method. So this is the example of that kind of problem.

3 forces of 30N, 45N, and 50N act on a body. The first is in the direction 50* west of north, the second is in the direction of EAST 30* NORTH and the third is on the bearing 135*. Find the resultan force...
Here is the solution:
















































There is another method we can use to solve this type of problem ..... the triangle method, it is somewhat similar to paralellogram method because they using the same angles to solve a problem,,, their only difference is that triangle method is using a tringle.....

for the next scribe its Andrew




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Friday, April 21, 2006 

Vectors







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Thursday, April 20, 2006 

Today we had two periods. Mr.K was not present for today, but there was a sub Ms. Adam. she let us do our previous vectors homeworks and the assighments she handed out the previous day. then she assigned us group work. After that she gave us new assignment "Vector Problems set 3". Ask Mr.K on friday if you don't have one. Ms. Adam did on the board questions #4 and #8.
page 328.



#4. A small aircraft on a heading of [225] is cruising at 150km/h. it encounters a wind that blows toward [345] at 35km/h. find the aircraft's resultant velocity.



#8. A kayak is paddled at 8Km/h towards [330] while an ocean current carries the kayak at 3.2km/h towards [170], what is the resultant velocity of the kayak?

* i will post the graphical image of #4 later, but i couldn't upload the graphic image of #8.

* I think it would be nice if Mr.K showed us how to use the SIN Law, and when to use it, as it is sometimes a long method.

that's all folks.

tomorrow scribe is PATRICK. i was filling in for Patrick tonight, i.e. i fill in Patrick tonight, he would do the following night. Anywho bye byeeeeeeeeeeeeeeeeeeeeeeeeee.




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Magnitude and Direction

Scribe!!!

Here is my scribe now. Sorry for the delay. This was the work sheet we worked on Wednesday.
And since Mr. K wasn't in class to give us the answer here is what i got.

Measure vector V shown Below using ruler and protractor.


















1. What is the magnitude of the vector represented by the arrow? Show how you arrive at your answer. Be sure to include units with your answer.

Ans. Since we used this scale , 1 cm = 2.5 km/h, we have to multiply 2.5 to 10 cm (lenght of the arrow mesured with a ruler in cm).

lenght(cm) x Actual magnitude = Reality magnitude
10 x 2.5 = 25
reality magnitude = 25 km/h

2. What is the direction of the vector? Write the answer in five different ways.

Ans.
Bearing of 250 Degrees
70 degree south of west
west 70 degree south
30 degree west of south
south 30 degree west

That all folks. If my last answer is wrong please dont hesitate to post the right one.




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TO MR. K

Hey mr.k,
sorry fo the late post but i must let u kno that i will not be attending Thursday's, or tomorrows class cause i will b at sissler high school attending the workshop for my law class and yeah i will get wat i missed from the scribe that day k good nite buh bye




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Wednesday, April 19, 2006 

Magnitude and Direction

Scribe
April 19 2006

Hey you guys. My scribe will not be up today. IT will be up Tommorow as soon as I get the Right answer for the questions. Anyways Pa3k is the next scribe




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Tuesday, April 18, 2006 

(>O_o)> .:Vectors:. <(o_O<)

Hi everyone, today we did a lot of stuff in our class because we had two periods of math today, so let's get it started. At the beginning of the first period class, Mr. K gave us some problems to solve and he also reminded us about SOHCAHTOA. SOHCAHTOA means Sin= O/H, Cos= A/H, Tan= O/A. O means the opposite, A is the Adjacent ( Next to; neighboring) and H for Hypotenuse (Note: The hypotenuse is the longest side of a right triangle).
*Sin^-1, Cos^-1, and Tan^-1 are called
Arc Sin, Arc Cos, and Arc tan......This functions means the same thing.*

Here are the problems that Mr. K gave us:
1) Find: tan A, angle A, Length of AC


A) Tan A= O/A
Tan A = 5/12
Tan A = .4166

B) Angle A = arc tan (.4166)
Angle A = 22.61 degree

C) Length of AC
C^2= 25^2 + 5^2
C^2= 169 (Take the square root of C^2 and 169)
C = 13

2) Find: Sin R, Angle R, Length of QR


A) Sin R = O/H
Sin R = 11/25
Sin R = .44

B) Angle R= arc sin (.44)
Angle R= 26.10 degree

C) Length of QR
25^2= 11^2 + a^2
(25^2)-(11^2)= a^2
504 = a^2 ( Find the square root of 504 and a^2)
22.44 = a

3) Find : Length of XZ and length of XY


A) length of XZ
Cos 37= 32/H
H= 32 / Cos (37)
H= 40

B) length of XY
z^2 = x^2 + Y^2 - 2xyCos Z
z^2= (32^2 + 40^2) - (2*32*40*Cos (37))
z^2= 579.49 (square root both sides)
z= 24.1

4) Find: length of AC, Angle A



A) length of AC
b^2= a^2 + c^2 - 2*a*c*Cos B
b^2= (5.7^2 + 4.5^2) - (2*5.7*4.5*Cos (78))
b^2= 42.07 (square root both sides)
b= 6.49

B) Angle A
a/Sin A = b/SinB
5.7/Sin A = 6.49/Sin (78)
Sin A = (5.7*Sin (78))/6.49
Sin A = .8591
Arc sin (.8591)= 59.21 degree

5) Find: Angle C, b


A) Angle C
a / Sin A = c / Sin C
5.1 / Sin (28) = 3.8 / Sin C
Sin C = (3.8*Sin (28)) / 5.1
Sin C = .3498
arc Sin (.3498) = 20.47 degree

B) length of b
Step 1: Find Angle B so that we can use the sin law or the cos law.
Angle B = 180-28-20.47 = 131.53 degree
Step 2: Use sin law ( it's easier to work with :P)
a / Sin A = b / Sin B
5.1 / Sin (28) = b / Sin (131.53)
b= (5.1* Sin(131.53) / Sin (28)
b= 8.13

Mr. K also gave us two kinds of programs for our calculater. The programs is used to solve triangles, If you missed the class today be sure to ask someone to give you the program.
To access this programs:

1) Press the [PRGM] Key and then press [1]. The calculator will use the sin law and the cos law.
2) Press [PRGM] key and then press [2]. This will identify all the missing angles and sides.

For the second period of math, Mr. K gave us more problems to work on:

1) Hezy and Partick paddle their canoe 5.5 km west and then 4 km south. How far are they from their starting Point? What direction must they paddle to return to the starting point by the shortest route?




Therefore they are 6.8 km away from the starting point and must paddle north east to return to the starting point.

2) Forces of 210 N and 85 N act at an angle of 78 degree to each other. Find the resultant force and the angle it makes with the smaller force.
The resultant force is 242.38N, at 57.94 degree to 85N force. (sorry that I can't show you guys the solution but I'll have the solution by tomorrow).

Well today has been a crazy day and our homework is on page 322, numbers 1-4 and the next scribe will be (>O_o)> .: HEZY :. <(o_O<) .




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SCRIBE

Hi Im your scribe for today. Well Im sorry I couldnt put the post up earlier. I was put on the spot by somebody so go easy on me lol.

Today in class we did a review on vectors.

Vector: a diagram which shows both direction (North,East,South,West) and magintude. Ex. of magnitude (force,weight, distance,etc.)

We learned about the 5 different directions.

Ex.
They are as follows:

Bearing of 045°
North 45° West
East 45° North
45° North of East
45° East of North


Notice that they are all different but mean the same thing. Same direction

*Note right angles are equal to 90°. (45+45=90)
Same as if the angle was 60°. (60+30=90)

We learned how to add vectors to find the resultant. Ex. Tug-o-war A force of 50N pulling east and a force of 60N pulling West.







Resultant is 10N west











Another Example:
Pulling a tree stump out of the ground. A force of 50N pulling West and a force of 50N pulling at a bearing of 40°.


We can make a copy of the vector and add it to the original one. Because it has the same direction and magnitude we can do the following to help find the resultant.








Example 2:
Given the same exact diagram but different situation. A golfer hits a ball 50ft west and 60ft with a bearing of 050°

The following example is a triangle. You can now use the Cosine law to figure out the resultant vector. c2=a2+b2-2abcosC



*Note the Cosine Law only needs to be used once and should only be used if met under one of these circumstances:

You are given side, side, side
or side, angle, side (which was given in this example).

Well this is what we did in class. Hopefully you can understand it.

*Homework was what we were given before pg 307 #'s 1-8
and the new stuff is on pg 318 #'s 1-9*

Next Scribe is the only person left which is Reign. Then it starts all over again.
Cya




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Saturday, April 15, 2006 

Blogging on blogging

What can I say about statistics.. I think firs time I had hard time understanding, but right now I’m doing well. And also I believe the only way to understand this unit is to do more work. I guess the sheets that Mr. K gave us were very helpful. Good luck guys




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Wednesday, April 12, 2006 

Blogging On Blogging

I guess I'll start this post off by saying what everyone's been saying which is, the statistics unit was very hard. And apparently I haven't been doing well. The toughest part of the whole unit, in my opinion, was the confidence interval. I'm actually okay when it comes to doing the calculations. My only problem is understanding what the numbers mean and what's actually going on in a certain problem. And because I don't know what's going on in a problem, I tend to do the wrong things and make mistakes trying to figure out what the answer might be to that problem. IF I'm LUCKY, I might actually pass the test. At least I know that I'm going to get ONE mark for having this blogging on blogging post done. }:-(

*REMEMBER SISYPHUS!* {;-)




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Blogging on blogging

I had a really hard time understanding this section (stastics) but now i kinda get it. I think the only key to pass this section is try and try examples and thats what i did. It really helps to stick to someone that knows this stuff. Patrick and Reign helps me to understand and me as well corrects them ,a little bit, if i knew i was right. The last 2 sheets that Mr. K gave us, really helped me. Thats all I can say. Good luck to you guys and take a good look at the calculator commands, Math vocabulary and i was hoping that Mr. K will post some practice quiz today.




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blogging on blogging

the first few classes of this unit I thought was really easy but as we got more into depth with the unit I started to have trouble with it. my only trouble with the unit is the calculator functions, I keep getting mixed up with what functions go with what questions. butwhen we did the pretest I did ok and I wasnt having much trouble. now I just have to practice understanding what the questions are asking for. to do that I just need to practice doing more problems. hopefully I do ok on the test tomorrow. goooood luck everyone!




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Tuesday, April 11, 2006 

blogging on blogging

well this unit sure was difficult. the first few classes weren't that bad. learning to calculate mean and standard deviation was a piece of cake. but as classes went on, i'd have to say that the stuff that i kinda got but kinda got confused was the binomial ones. like today the sub handed out worksheets and there were questions like question 6 on the first worksheet that was handed out. but with a little team work, i was able to get it and understand how it was done. so a little more practice with that should be good. yeah. kay, gnite, bye!




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Blogging On Blogging

I agree with my other classmates that statistics is hard, because i otfen find myself having trouble with some of the questions from the probability unit.....Our 3rd unit on statistics is somewhat confusing as well, because of those many calculator comands that need to be remembered. There is more than one way to solve a problem using the calculator, that's what made me confused in the begining, but my own way to compensate to that problem is to remember only one calculator command that can gave the same answer, like for example getting the area of the normal curve graph can be get by fidding z-scores then use shadenorm to show the graph, and the other way is solve it directly without showing the graph, so from those 2 steps i just oftenly use one of those and stick on it because it gave the same answer anyway, in that way I never be confused what calculator command to be use....This unit, in my opinion is really helpful because the data, the problems,the solutions, etc, can really applied in everyday life.




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Monday, April 10, 2006 

Blogging on Blogging

Well Statistics is easily the hardest chapter that we have covered. Its really really calculator orientated. I think thats what sets it apart from most units. I pretty much understand most of the unit. It's kinda weird but i understand most of the later stuff we did in the unit. I'm really gonna have to review the early stuff we did in the unit. The Statistics test is gonna be a test I'm gonna have to study for. I'm just gonna review my dictionary or read the blog and do some review questions. If I do all this I think I should be fine. I did better on the pre-test than I expected. But thats not saying much cause I didnt have the highest expectations for it. I fluked out few anwsers which was kinda suprising.

Well thats about it.
Cya.




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SCRIBE

Hey whats up everyone. Im the scribe for today so I'll go over what happend in class today.

First thing at the begining of class Mr. K handed back a bunch of old work for past units. All I can say from looking at my marks then is I miss the marks i got in the Marticies unit. Anyways I think after that Mr. K anwsered some questions people had on blogging on blogging. I'm not sure what the origional question was but it involved finding the area of part of a curve multiple ways.

The first example he gave was find area of everything under the Z score of -2. One way to do it is: by using shadnorm function of your calculator. With using shadenorm with Z scores the first digit you plug into your calculator is the low value, which in this case is -5. ( this is because, I'm not quite sure of this number but 99.99% of data is between 5 standard deviations, so using -5 is more than enough to get everything on the low end) Then you hit , then plug in the high value, in this case it would be -2. This is what You should get. (note: shadenorm draws a graph)

shadenorn( -5,-2)= o.o25

Another way to do the same question is by using the normalcdf function of ur calculator. The only difference between shadenorm and normalcdf is shadenorm draws a grapgh.

Normalcdf(-5,-2)=0.025

Another way to do the same type of question is with using the real/normal values not the Z-scores. Basically the only difference between this and the question above is when using the normal values you need to plug the mean and standard dev. into your calculator along with the low and high values. The Mean for the example was 62 and the standar dev. was 6. We were supsota find the % of data up to the Z score of -2. Well one way of finding what the normal value of a Z-score of -2 is with the mean of 62 would be to plug it into that formula:
z=x-x(mean)/standard dev. But and easier way to do it would be to just to subtract the amount of Z scores you want to find from the mean. Kinda hard to explain. The low value we want to find sould be equal to -5 Z-scores like in the first example. And one Standard dev. = 1 Z-Score would to find -5 Z-score would would take the mean and subtract it from 5 standard dev.

62-(5 x 6) = 32 < this is our low value

So to find the high score you basically do the same thing but you only subtract 2 Z-scores for the mean

62-(2 x 6)= 50
Then all you have to do is plug the information you have into your calculator. You can either use shadenorm or normalcdf. Either way you should get the same thing

shadenorm(32,50,62,6)= .025
normalcdf (32,50,62,6)= .025
(remember you have to plug in the mean and standard dev. to let the calculator now that your not using Z-scores)

And then after this we were given our statistics pre-test. After that we got into groups to discuss our anwsers and then like usual only one person had to hand one paper with the group members names on it. Well thats about it for what we did in class today. The last thing I got to say is remember to do your blogging on blogging before your test. I'm gonna do mine now while I'm logged into blogger.

Cya




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Blogging on Blogging

statistics was the hardest chapter of all. i think. doing more problems helped us alot. if we would have done the pre-test on friday. i think the result would have been bad. what scares me on this chapter is when the question doesn't mention what type of distribution to use. it lets you figure out what type of distribution to use. Doing this part is the hardest of all to me. i have couple of problems. that i would love to see answered in class, after the pre-test, before the real test. the question are as follows:


1) The weight of babies born at HSC averages 8 lbs, 10z (there are 16.0z in 1 lbs).

a) Find the percentage of babies with a birth weight between 7 lbs and 9 lbs.

b) Find the weight , w, such that the percentage of babies with a birth weight greater than w is 60%.

c) Find the weight w, such the percentage of babies with a birth weight less than w is 25%.


2) A college aplitude is scales 5000 that its scored approxiate a normal distribution with a mean of 500 and a standard deviation of 100.

a) find the probability that a student selected random will score 800 or more points.

b) find the score x, such that 76%, of the student have a score.

i) less tahn x
ii) more than x

*that! thats all folks.




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Sunday, April 09, 2006 

Blogging on Blogging (Statistics)

I found statistics the most hardest chapter so far in this course. But as we do more problems in class it gets more easier to understand these type of problems. But still i have some problem in understanding the (binomial,pdf and cdf) and (invnorm) commands in calculator. I can't figure out when to use these commands. But if we do a few more problems in class based on these commands then i think i will be ready for the test.




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Blogging on blogging

Statistics is the second hardest lesson that we have done because there are a lot of things to remember specially on the calculator part. I always have to read my dictionary and do my homework so that I can remember all the stuff that we have learned during that day because if haven't read my notes or do my homework I would probably be lost right now. Finding the mean, z-score and the unknown values was the easiest part of the lesson, but IM having a little problem on using invnrom because I don't know when to use it. The binomial distribution, normal approximation and confidence intervals are the hardest questions to do. I think that if we spent a little more time on doing exercises with this type of questions will help me understand them better and hopefully be ready on our test this Thursday.




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Scribe for The Day Before yesterday!!!!!!!!!!!!!

Hey folks, sorry i'm a bit late on posting my Scribe post, Computer problems, you see.

Anyways, on friday, we did mostly problems, in preparation for our Pre-Test on Monday. This was helpful, as i now understand what we were doing in this unit.

Here are the Questions:


Let Them Grow!

The Following Data represents the ages of trees drawn as a random sample of trees in a park in manitoba. The DAta were collected by park officials, and the numbers represent the number of rings in the trunk of the tree. Each ring represents one year of growth for a tree.

26 30 48 22 47 42 25 25 29 5 18
4 23 16 36 26 36 35 36 2 39 15
37 29 37 16 15 48 9 12 41 41 32
26 14 5 6 46 21 15 1 26 43 27


(a) Use your calculator to determine the mean, median, range, and standard deviation for the Data.

(b) Use the results of #1 to determine if the sample is normally distributed. Explain your reasoning.

(c) What would the Z-score of a tree with 33 rings be? Explain how you arrived at your answer.

(d) If you assume that the data aer normally distributed, what percentage of trees would have from 17-38 inclusive rings? Explain how you arrived at your answer.




ANSWERS:

(a) 1 var stats (L4)
_
X=27.72
σ=13.4323
Median: 26
Range: 1
σ= 12.295-39.18

(b)16/44=64%
(all within 1
σ)
_
(c)Z=(X-X)/
σ
=.39308
σ is 33 rings


(d) NormalCdf (17,38,27.72,13.4323)
=56.16%

(e)_ _
(X-
1.96σ, X+1.96σ)
-0.6,52.05

%margin of error: (1.96
σ)/n=.598
=59.8% margin of error.



At Aborder Crossing in Canada, customs agents decide which vehicles they will search for undeclared goods as the vehicles enter Canada. Records show that on average 28 percent of the vehicles searched contained undeclared goods.
A New Customs Employee, agent sparks, searched 392 vehicles and found undeclared goods in fewer than one hundred vehicles. The officer in charge, officer Pound, did not do so well in his high school math, but he does know that 28 percent of 392 is about 110 vehicles and so he gave agent sparks a reprimand and a pay cut.

In your opinion, did officer pound do the right thing in giving sparks a pay cut? Carefully explain your reasoning. Support your answer with appropriate statistical information.






ANSWERS:




P=.28
q=1-P
1-.28=.72
q=.72
_
X=np=109.76
σ= (npq)=8.8897



100/392=.25510
invNorm(.25510)
=-.6585

Sum of Prob:
P(<100>
=12.36%



The New Zeppos Are in!


Car Dealer Dan is selling a new car that has just arrived in Manitoba - A Zeppo. He tested 40 cars for gas consumption. and the number of miles per gallon for each car is shown in the table. Assume that the distribution is approximately normal.

30 34 31 33 32 29 31 24 25 33
34 3030 34 29 35 35 33 31 33
36 34 31 32 28 40 29 35 32 33
31 34 29 29 31 39 35 29 32 25


Questions:

(a)Find Mean And Standard Deviation for the Data. Round your answers to one decimal place.

(b)Find the probability that any car selected will have a fuel economy of 35 miles per Gallon (MPG) or better. Round your answer to on decimal Place.

(c) What percent of cars will drive from 27-37 Miles per gallon? He needs this information for his advertising campaign. Round your answer to three decimal places.

(d) Dan anticipates selling 400 zeppos in one year, and wants to offer up a free barbecue to any new car owner whose car does not measure up to a certain level of fuel efficiency. after one year of operation. he does not want to give away more that 20 barbecues. What level of fuel efficiency (in MPG should he guarantee? Round your answer to the nearest whole #.








ANSWERS:


(a)
_
X=32
σ3.46
_
(b) X-X/
σ= Z
(35-32)/3.46
=.867005
NormalCdf(.867005,5)
=.19296, or 19.3%

(c) 27-32/3.46=-1.445
37-32/3.46=1.445
normalCdf(-1.445,1.445)
=.85154, or 85.2%

(d) 20/400
=.05, 0r 5%


invNorm(.05)
=-1.6448536

(1.6448536)(3.46)+32=
26.3088, or 26 MPG he should guarantee if he only gives away 20 barbecues.



Good luck with the Math pre-test on monday morning!




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Four Colour Sunday!


You may have heard that any map can be coloured with four colours in such a way that neighbouring countries receive different colours. That it can be always done is one thing. How to do it is another. Are you ready to start colouring?

(Thanks again to Think Again!)




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Thursday, April 06, 2006 

SCRIBE FOR TODAY!!!!

Chello, Chello, Chello
Yes i am today's scribe and ummm i'm not sure how to put pictures on this thingy cause i'm not a big computer freak well i mean i just dont like drawing and i just dont kno how lol:) SRY
So when i put "DIAGRAM" threres prolly a diagram of a 95% confidence interval ok kool, here we go.

Today we started off with some morning announcements and then Mr.K told some jokes, one was really good that i thought was true and then the others were all right and yeah thats wat we did to start off our day :) Oh today was a single class day!

We also did some dictionary notes and here they are:

Constructing Confidence Intervals

Step 1: Decide on the desired degree of confidence
Example: 95%

Step 2: Determine, with the aid of a diagram, the area in the trials of the normal curve.
Example: A Diagram of a 95% Confidence Interval Goes here Sorry:)

Step 3: Using tables or InvNorm(area) on your calculator find the values of Z-score low and Z-score high.
Example: InvNorm(0.025) = -1.96
Z-score low=-1.96 Z-score high=1.96

Step 4: Use the values Z-score low and Z-score high to construct your confidence interval as follows: (Meu-Z score X standard deviation, Meu+Z score X standard deviation)
Example: The 95% confidence interval for a normal distribution with M=63 and Standard Deviation=8 is: (63-(1.96)(8),63+(1.96)(8)) OR (47.32,78.68)

Percent Margin of Error

For the normal approximation of any binomial distribution we find the percent margin of error as follows: % margin of error= Z score(Standard deviation)/ n X 100

Z score is the appropriate Z score to generate a given confidence interval.
Standard Deviation symbol is the standard deviation symbol
n is the total number of trials in a given binomial experiment
Example: Given the bove data taken from a binomial experiment that was done 50 times(n=50)
% margin of error= (1.96)(8) / 50 X 100% = 31.36%

Theres your dictionary notes for the day and sorry for my illeteracy for symbols and suff lol please forgive:)

Now today we looked at a table of Z scores in our book on page 355, that table we must know how to use because it will be given to us on our exam at the end of the year during the time when we cannot use our calculators.

Today we also did a little question on the board that involved constructing a 95% confidence interval and finding the % margin of error for the amount of people wearing jeans in a mall out of 340 people so here it is:

n=340 p=238/340 = .70
q=.30
M=np=238 (M-1.96(8.45),M+1.96(8.45))
nq=102 (238-1.96(8.45),238+1.96(8.45))
(221,255)

Standard deviation=the square root of npq
=square root of 340(.70)(.30)
= 8.45

% margin of error= (1.96)(8.45) / 340 X 100 = 4.87%

All of this means that if you repeat this experiment we are 95% confident that19 times out of 20 the data will fall between 221 and 255, so we will get an answer that is = to 238+/- 4.87%

We also have homework on PAGE 145 # 1-3, and we have a pre-test tomorrow so be sure to STUDY and dont forget k :)

Well that rap's it up for my scribe hope u can understand it lol but yeah have a good day and stuff BUH BYE THANK U

p.s tomorrows scribe will be NIK #1/2 :)




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Blogging on blogging

Well, it's that time again. Blogging in hope of finding answers before the test. So it's official, statistics is by far the hardest unit we've done. Well, that's what I think :P There are so many functions that you need to know on your calculator. I've found that if I haven't reviewed my notes for one night, it's hard to remember what did what, nevermind everything else you need to know. Finding z-scores and unknown values are easy. One thing I'm a bit 'iffy' on, is when you're given the percentage of the area under the normal curve and you need to use invNorm to find the value/z-score. But more importantly the most difficult problems are the binomial distribution, normal approximation and confidence intervals questions. It does take a lot of work to do the questions, but I think familiarizing ourselves more with the calculator is what's needed. Hopefully, with the help of a lot more practice, I can get everything figured out..




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Tuesday, April 04, 2006 

SCRIBE

How you guys doing?

It’s just another bad day for me, and I’ll tell you why.
First, we had only one class today and Mr. K gave us a quiz but I thought it was just a group work, and I did very bad this quiz. It was 10\10. Guess how much I got. I did very badly that is not means I got 1\10 but if you think that, then you are too close. I got 3\10 but don’t think I’m stupid, because I did very badly, at the same time I’m still telling you that I did bad, but here is what I want to say, that was my mistake. I knew the material but I just misunderstood but you know it was a experience for me because I’ll never do it again at the same mistake.
Mr. K said anybody who got less than 8\10, you are in trouble, then what you think about me, I’m in a big trouble, but remember not only me I know somebody else also in a trouble.
So why can’t we come up with something different.
I get one suggestion and let us hear from you or give us your view.
Here is what I would like to suggest, first, if you understood the material and you know you doing fine, ask your friend or other classmates if they have a trouble or if they don’t understand what is going on, because you can help them, and also I believe they feel comfortable with you. If you don’t understand the material or you think that you need little help ask your friends say I need help and that is not shame that is how you learn.

Those who have time the days that we only have one class, let us come together and do something constructive i.e.(Homework).
If we come together, I’m telling you we can do a lot and I have experience for that, because before the spring break I had trouble with probability but in spring break we were meeting every two days once me , Caitlin and Mohamed. We couldn’t believe it how much we can do it. And that was helpful. Thanks Caitlin and Mohamed.

The rest of the period it was just writing notes in our dictionary.
Here you go

MORE CALCULATOR FUNCTION YOU SHOULD KNOW

TO FIND THE AREA UNDER THE NORMAL CURVE BETWEEN 2 KNOWN Z-SCORES

METHOD ONE

Calculates the area and draw the graph.
ShadeNorm(low value, high value, mean,STD.Dev.)STD.Dev Means standard deviation.
If you do not enter values for mean and STD.Dev. the calculator uses the standard normal curve; i.e. Mean=0 STD.Dev=1
Access: 2nd [Vars] [>][1]



For the standard normal curve we uses these { window} settings

Xmin=-5 Xmax=5 Xsc1=1
Ymin=-.2 ymax=.6 Ysc1=.1
Adjust the window setting if you use the values of Mean and STd.Dev that are different from the Mean=0 and STD.Dev=1.

Method two

Calculate the area; does not draw a graph.
Normalcdf(law value, high value, Mean, STD Dev.)
Access; 2nd [vars][2]

If you want to find the Z-Scores from which you know the area under the curve and below that Z-Score:

InvNorm[area}
Access: 2nd [Vars][3]

If you want to know the probability that a particular value will occur in a normal distribution.

Normlpdf {Value, Mean,STD.Dev}
Access: [2nd ][Vars][1]

The above command is similar to the one below in a binomial distribution, to calculate the probability that a particular number of “successes” will occur we use:

Binompdf(# trial, probability, of success, # success)

If you want to list (and perhaps store) the probabilities for all possible (# of “successes”, for zero to the max omit. The last parameter

Binompdf(trials, probability of “success”

Access[2nd ][Vars][0]


To find the sum of the probabilities in a binomial distribution between two given “number of successes”
(this similarto using ShadNorm, or Normalcdf for normal distribution )

We use: binomcdf(# trials, probabilities of success, low # successes, high # successes)
Access: [2nd ][Vars][A]

I think that is all for today.
Make sure that you did your homework page 130 #1-8.
And also think about your blogging on blogging.

I want to see changes done by this Thursday, because we only have one class.

There is two things can happen, whether you help for someone, or you get help.


NEXT SCRIBE IS RUBIE




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Why Should I Learn Math?

This is taken from an article (Math Will Rock Your World) from Business Week. A few snippets:


Y'wanna get a really interesting job working with people on lots of interesting things?



But just look at where the mathematicians are now. They're helping to map out advertising campaigns, they're changing the nature of research in newsrooms and in biology labs, and they're enabling marketers to forge new one-on-one relationships with customers. As this occurs, more of the economy falls into the realm of numbers. Says James R. Schatz, chief of the mathematics research group at the National Security Agency: "There has never been a better time to be a mathematician."


Learn math!


How'd ya like a six figure salary?



...new math grads land with six-figure salaries and rich stock deals. Tom Leighton, an entrepreneur and applied math professor at Massachusetts Institute of Technology, says: "All of my students have standing offers at Yahoo! (YHOO) and Google (GOOG)."


Learn math.


D'ya wanna to work on the biggest most cutting edge issues of our day?



This mathematical modeling of humanity promises to be one of the great undertakings of the 21st century. It will grow in scope to include much of the physical world as mathematicians get their hands on new flows of data .... "We turn the world of content into math, and we turn you into math," says Howard Kaushansky, CEO of Boulder (Colo.)-based Umbria Inc., a company that uses math to analyze marketing trends online.


Learn math.


Y'wanna make one of the most significant contributions to the betterment of humanity?



"The next Jonas Salk will be a mathematician, not a doctor."


Learn math.


What are the implications for k-12 education?



Outfitting students with the right quantitative skills is a crucial test facing school boards and education ministries worldwide. This is especially true in America. The U.S. has long leaned on foreigners to provide math talent in universities and corporate research labs. Even in the post-September 11 world, where it is harder for foreigners to get student visas, an estimated half of the 20,000 math grad students now in the U.S. are foreign-born. A similar pattern holds for many other math-based professions, from computer science to engineering.


The challenge facing the U.S. now is twofold. On one hand, the country must breed more top-notch mathematicians at home, especially as foreigners find greater opportunities abroad. This will require revamping education, engaging more girls and ethnic minorities in math, and boosting the number of students who make it through calculus, the gateway for math-based disciplines. "It's critical to the future of our technological society," says Michael Sipser, head of the mathematics department at Massachusetts Institute of Technology. At the same time, school districts must cultivate greater math savvy among the broader population to prepare it for a business world in which numbers will pop up continuously. This may well involve extending the math curriculum to include more applied subjects such as statistics.



Learn more math!


"But I don't like math. Besides, I don't need it. I'm going into the humanities or business!"



As mathematicians expand their domain into the humanities, they're working with new data, much of it untested. "It's very possible for people to misplace faith in numbers," says Craig Silverstein, director of technology at Google. The antidote at Google and elsewhere is to put mathematicians on teams with specialists from other disciplines, including the social sciences.


Just as mathematicians need to grapple with human quirks and mysteries, managers and entrepreneurs must bone up on mathematics. Midcareer managers can delegate much of this work to their staffers. But they still must understand enough about math to question the assumptions behind the numbers. "Now it's easier for people to bamboozle someone by having analysis based on lots of data and graphs," says Paul C. Pfleiderer, a finance professor at the Stanford Graduate School of Business. "We have to train people in business to spot a bogus argument."



Ya gotta learn more math!



Yes, it's a magnificent time to know math.


'Nuff said.




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Statistics (Blogging on Blogging)

I'm really struggling with tonight's homework (page 130). It' s strange, because I thought I understood it in class, but now it looks like a bunch of gibberish to me. I have an okay grasp on the stuff we did before this. I hope you guys understand this better than I do. :-/




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Monday, April 03, 2006 

Scribe

Andrew here, and today we had two classes.

In the morning Mr. K reminded those who haven't tagged three sites must do so and there will also be a test next week. There were two problems we had to do and it took the whole class time to do those questions, mainly the second one.


1. 1200 light bulbs were tested for the number of hours of life. The mean life was 640 hours with a standard deviation of 50 hours. Assume the life in hours of light bulbs is normally distributed.

a) What percent of light bulbs lasted between 600 and 700 hours?

Z = (600 - M)/S = -0.8

Z = (700 - M)/S = 1.2

ShadeNorm(-0.8 , 1.2) = 0.673075


b) How many light bulbs could be expected to last between 600 and 700 hours?

0.673075 * 1200 = 807.69


Now the second question (which uses binomial distribution) took the morning class and the second class to answer, PLUS we had to do another question (which uses binomial distribution and normal approximation).

2. A shipment of 200 tires is known to include 40 defective tires. 5 tires are selected at random and each tire is replaced before the next one is selected.
What is the probability of getting:

a) at most 2 defective tires

First find the probability of getting a defective tire.

40 / 200 = 0.20

Also, make a list in L1. Your list should look like this:


Go to the home screen and press 2nd function VARS to go to the distribution menu and select the binompdf ( .

binompdf(# of trials (n) , probability of success (p))

binompdf( 5 , 0.20) -store-> L2

L2 should look like this:



To find the answer to a) you must go to the home screen and press 2nd function STAT and then go to the MATH menu and choose sum ( . SUM will add all the probabilities from the lowest value to the highest.

sum( List , low value , high value )

sum(L2 , 1 (refer to the 1st image; you are actually choosing ZERO on the L1) , 3 (you are choosing TWO because at most you have 2 defective tires.)) This syntax should look like this:

sum( L2 , 1 , 3 ) = 0.94208


b) What is the probability of getting at least 1 defective tire?

sum( L2 , 1 , 1 ) = 0.32768

1 - Ans = 0.67232 , 0r , sum( L2 , 2 , 6)

The sum( L2 , 2 , 6 ) answer seems easier to explain, so the defective tire can either be the 1st, 2nd, 3rd, 4th, or 5th tire which is why the lowest value is 2 and the highest value is 6.


c) What is the probability of getting 2 or 3 defective tires?

sum( L2 , 3 , 4 ) = 0.256


And finally, on to question 3.

3. Customs officers estimate that 10% of vehicles crossing the Canada-US border carry undeclared goods. One day they randomly searched 350 vehicles. What is the probability that 40 or more vehicles carried undeclared goods?

n = 350

p = 0.10

q = 0.90

Now there are 2 methods to solving this problem. ONE being the binomial distribution method, the other being the normal approximation method. There are also 2 methods within the normal approximation method. You can either use Z-scores or RAW data.


Binomial Distribution
: Uses n and p.

binompdf( 350 , 0.10 ) -store-> L1

sum( L1 , 41 , 351 ) = 0.2088192368


Normal Approximation:
Uses n, p, and q.

Method 1:
Z-scores
(Note: I'm still unsure of what to actually do since I sort of forgot how to do this)

M = n*p = 35

S = square root (n*p*q) = 5.61248608

Z = (40 - M) / S = 0.8908708064

Z = (350 - M) / S = 56.1248608

normalcdf( low value , high value )

normalcdf( low Z , high Z ) = 0.1864992046

Method 2: Raw Data

normalcdf( 40 , 350 , M , S) = 0.1864992046

(Note: for some reason using binomial distribution and normal approximation gives different answers but are also really close, and I have no idea why)


WELL, that's about all we did in both classes. Anyone who reads this should make COMMENTS in case I've made mistakes.

HOMEWORK: page 130, questions 1-8

NEXT SCRIBE: Muuxi




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Sunday, April 02, 2006 

Roboclaw Sunday!


Move the robot arm to pick up the ball. Clean, simple design. I got to level 19. I died. It's a doozy!




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