*** official ap statistics 2013 thread ***

<p>You didn’t have to root 12 for a since it asked for a randomly select full carton, and carton is 1 so you root 1 which is just 1 and you get 10%</p>

<p>In all of the standardizing I’ve done, I’ve never divided the SD by root n, so I didn’t do it here. Could go either way…</p>

<p>there weren’t 12 cartons there were 12 eggs and the question wasn’t asking for eggs</p>

<p>Yeah, it was asking about cartons, so I did not divide by square root of 12. I just realized, I entered 559 instead of 669 for one of the values in the age vs consumption question… my p value was like 2.5 x 10^-8. Ehh that means I didn’t get an E for that one, oh well.</p>

<p>i just reread the question and it seems that the wording tripped me up and that u would not need to divide by root 12 because the 7.9 was for each carton and the sample was one carton</p>

<p>aka divide by root 1 which is root 1 (you divide by root n to find the standard deviation of the sample, to put the statistics in terms of the sample)</p>

<p>I thought the FRQ were so much easier than the MC, some of the MC were complete jokes, but some were pretty difficult</p>

<p>but you would have to divide by 12 for the sd which i missed so everyone misses stuff so it’s no big deal</p>

<p>agreed but some of my stupid mistakes on the frq might get me a 4 instead of a 5, unless my mc was over 28</p>

<p>Yeah, we took like 2 or 3 practice exams in class and I was right on a 4/5. I thought I did much better on the FRQ section of the actual exam though. For the most part, the MC was easier than the practice exams with a few difficult ones that I probably could have gotten if I had studied some minor details.</p>

<p>we got a book full of like 6 practice exams and my mc was like 25 (at worse) and like 32 (on a good one) and right now i think i got around 5-10 on the exam so hopefully my assumption is correct, if not i got a 4</p>

<p>Not sure if this has already been addressed but in the released FR questions it seems they have corrected the x-axis in the #5 chart to read -0.02 and not -0.2.
So I think it’s safe to say there was a typo–not sure how they’ll handle it scoring-wise.</p>

<p>Hey everyone. </p>

<p>What did you guys get for the question on the MC that asked about a kid who ran a 1 prop z test and said that he was wrong. It asked what he should have done. I think the only possible answers were he should have run a 2 prop z test or a chi squared test should have been an option? </p>

<p>What did you guys get?! Let me know!</p>

<p>I said chi-squared test.</p>

<p>Did anyone get 5c about the histogram and the asked about pm -pc? I said that 0 is not in the interval so you cannot reject H0</p>

<p>If 0 isn’t in the interval that means you should reject H0 (because that means it is unlikely a difference of 0 will occur purely by chance).</p>

<p>Yeah Nidget is correct on rejecting the null if 0 is in the interval. and CALCvsSTAT… it all looks the same as long as you have enough information written down… it just saves you a LOT of time by using ellipses ‘(o-e)2/e + … + (o-e)2/e’ …</p>

<p>And definitely the multiple choice was more complicated than the free responses. Some were easy, some i’ve never even seen before. But good thing you can miss atleast half of the questions and still make a 5 on the exam. :)</p>

<p>Yeah Hadiram… All the calculations made with that problem will be off… Like miu of x and standard deviation… Wonder what will happen?</p>

<p>wait for 5c i said 0 is in the interval? can someone explain</p>

<p>So 0 was in the interval right? i means thats what you can say by eyeballing it. my stats teacher estimated each bar and then a N=10000 t interval! and he got a very narrow margin of error. his CI did not include 0!
but I dont think they expect you do all that on the AP lol</p>

<p>Also if 0 is in the interval, then you fail to reject H0 right?</p>

<p>^chess123 is correct. If 0 is in the interval, then it means that there may be no difference between the two values. Thus, since the null is a statement of no difference, we fail to reject the null.</p>