***OFFICIAL AP Statistics Thread 2014-2015***

@Jasondinh1 Not perfectly sure if this is what i wrote but I found the p value from the CI and then tested it on a .05 alpha level and rejected the null because there was sufficient evidence.

@APmaster007 there was no way it was a test of homogeneity, it was 100% a 2 proportion z test…

This test has a bunch of opinion questions. Not a good thing. I really don’t appreciate it.

The reasoning for part b on 5 is that a line of y=x will graph points where the amount of x is equal to the amount of y, which is what the question was actually asking. That would be a square body, and if anything is above the line, y is greater than x.

If everyone is saying it is a 2 proportion z test, then i guess I;m wrong.

I put mean 7 and sd of 12

I put mean 7 and sd of 12

@apmaster007 neither

The idea that it was a test of homogeneity is preposterous. It gave two proportions clearly and even if it was a chi-squared test it would be of independence (which it isn’t)

There was one question asking about people getting cancer. I picked “you can’t conclude anything cuz these people are volunteers”.
I thought I was right until I saw frq #4.
I was like dude ur kiddin me.

For the probability distributions of ATM’s, how did you find out the probability of all three working given at least 1 is working. I did something weird where I recreated the distribution without 0 of them working since it was given at least 1 was working and then weighted all of the other probabilities to equal 1 but i dont think it was right.

it was 7 and 36. Also what were the blocking methods? A lot of my friends and I also had trouble with that one… Seemed like there was no consensus.

I don’t think that they would give any kind of chi-square test without a table…

i put 7 and 12 because sd can be multiplied but not added so 4(3)=12 but don’t add 3

3 part b is the question that is slightly different from part a, but what you said is from part d

@Gatortristan its 36 - variance is 4. so square root of 4 is 2 -> 2 is SD. Multiplied by 3 is 6, and then square that to get the new variance.

Wasn’t it for variance though?

Well I’m floating on a thin line between a 2 and a 3 lol

I hope the curve is a 35-39% for a 3

Cant talk about the exam