<p>So, if I had the mean time that I ate dinner, talked with my family, and watched a movie for a week, can I add them together to get the mean time I spend doing all three? And if you had the standard deviations can you find that too?</p>
<p><em>Hint hint</em></p>
<p>^ Actually, you’re probably right.</p>
<p>I was just generally confused on that question.</p>
<p>I think you could add both of them.</p>
<p>Where you watching <em>E</em>llen Degeneres by any chance?</p>
<p>I would said stdev couldn’t be combined since they aren’t independent. But mean can…</p>
<p>For a bionomial stdev, is it:
sqrt(pq/n) or sqrt (pqn)</p>
<p>No, root(p(1-p)/n) wouldn’t work, because if you think about it, that would be a really small standard deviation in the context of the problem. You simply had to use root(p(1-p)n) and assume normality of the binomial distribution because np>10, n(1-p)>10, and use the normal approximation.</p>
<p>it def was not binomial distribution!
and for the celsius problem, i dont understand why it was so hard. it would just be
(5/9)^2 (5)^2</p>
<p>biologyrock is wrong! if you square both b2o2 - equals variance, you need to eliminate the sqaures for sd!</p>
<p>wowww, i love how i just realized i didn’t use the binomial/geometric formulas on the test ONCE. lmao, awesomee.</p>
<p>did anyone use a t-test on the open-endeds besides me?</p>
<p>ALSO, i have been wondering about the grading system on the open-endeds. i heard somewhere that you get +1 point for every correct statement. but, how could that be when some questions have four or five parts to some of them [ie #6]? can someone clear up this mystery? lol.</p>
<p>o yeah sorry forgot that. yeah u have to square root it sorry for the confusion
and it definitely wasnt BINOMIAL DISTRIBUTIOn</p>
<p>yes for number 5 it was 2 sample t test</p>
<p>yes! got #5 right then, but i never wrote the formula down, I just did it all on my calculator 
We should make a thread where people reply on how much of the fre response they completed. By the people here we could get a good idea on how curved this free response may be. I only did like 70% of the free response and had to BS like %20 of it</p>
<p>The questions are graded on a scale from 1-4. Each part is given an E (excellent or something >_>) P (partial), or I (Insufficient.) Then those get converted to the 1-4 scale. Ex: All E’s -> 4
2 E’s 2 P’s -> 3
etc.</p>
<p>I did all of the free response, but I think I got no.4 (the car problem) completely wrong. I’m pretty confident about the rest of it though.</p>
<p>yo ap grader imma let you finish but the two sample t test is the best test of all time</p>
<p>I’m a sophomore that hasn’t yet taken an AP stats class but I took the exam anyway( with ALOT of studying). I think I probably got a 1 or 2, hopefully 3, but most of the questions you could derive with a basic knowledge of trig/statistics, and knew all of the one’s that had to do with science experiments, anyway how many points would I need for a 2 or 3?</p>
<p>3 is a 34%. 2 is probs like…a 20%.</p>
<p>… I don’t think trig would’ve helped you in any part of the exam.</p>
<p>Generally:
78-100: 5
53-67: 4
40-52: 3
29-39: 2
0-28: 1</p>
<p>WOOOW I would have gotten full points if I had done sqrt np(1-p) but instead I did np(1-p). epic fail. That and 2 were the only one’s that got me. Oh well.</p>
<p>was one of your answers for the MC: mu1 + mu2</p>
<p>no, the answer to that was E, the one with the “it would be normal” because if M1-M2, then that would be the answer</p>