<p>where can we find the practice tests for ap stats?</p>
<p>Null hypothesis should be the one with no difference between the two treatments.</p>
<p>Someone already said this earlier in the thread but Null Hypothesis is the one that is always equal to something else. Alternate Hypothesis is for less than and more than.</p>
<p>A recent study was conducted to investigate the duration of time required to complete a certain manual dexterity task. The reported mean was 10.2 seconds with a standard deviation of 16.0 seconds. Suppose the reported values are the true mean and standard deviation for the population of subjects in the study. If a random sample of 144 subjects is selected from the population, what is the approximate probability that the mean of the sample will be more than 11.0 seconds?
a.) .1151
b.) .2743
c.) .7257
d.) .8849
e.) Based on the values of the true mean and true standard deviation, it can be concluded that the population distribution is not normal and therefore the probability cannot be calculated.</p>
<p>The answer is B but i keep on getting .48 from normalcdf(11, infinity, 10.2, 16)
What am i doing wrong?</p>
<p>** When do we pool? **</p>
<p>I asked my teacher today and he said to pool when p1 and p2 in the null are independent, but I still don’t get it…</p>
<p>Ok I know someone may have already brought this up, but whats the deal with writing calculator functions on the FRQ part. I know they dont want to see you writing normalpdf(blah, blah, blah)-but when is it appropriate.
I was doing an FRQ from the 2008 exam and on the answers they wanted u to find the expected values for each one by hand.
I mean if I have to do all the calculations by hand, isnt having a calculator a waste?</p>
<p>So could someone please clear up what is and isn’t acceptable as far as writing calculator functions?</p>
<p>^ you can use “+…+” only showing the first and last values in your addition sequence, particularily on E(x).</p>
<p>And don’t write “binomcdf ( )” on the test. Write out the “n over k” formula.</p>
<p>but after the formula i can just use what i found in the calculator right?</p>
<p>^ I think so, yes. </p>
<p>And on inference tests and confidence intervals, you don’t need to show ANY work for the test statistic/p-value/confidence interval if you correctly name the test before the conditions. You can just punch it into the calculator and write</p>
<p>“T = 3.453, P=.047” without any work to back it up. </p>
<p>And for confidence intervals you can just write what kind of CI it is and then put the interval without dealing w/ the critical value or the formula. ONLY if you name it before hand though.</p>
<p>Can someone please explain number 38, 23, 19, and 17</p>
<p><a href=“http://www.jonescollegeprep.org/ourpages/auto/2008/5/2/1209733393741/ap%20stats%202007%20complete%20exam.pdf[/url]”>http://www.jonescollegeprep.org/ourpages/auto/2008/5/2/1209733393741/ap%20stats%202007%20complete%20exam.pdf</a></p>
<p>thanks so much. They are weird questions that I’ve never encountered before. They are official from 2007.</p>
<p>^ I was JUST getting tripped up on the exact same problem today in class. Someone please do explain…</p>
<p>EDIT: I figured it out.</p>
<p>I narrowed it down to D or E. </p>
<p>It’s saying that if you play the game twice, the Y value is the SUM of your two scores. Obviously this y-value can encompass any value 0-4 so A-C are out of the question.</p>
<p>Then just write out all the possible combinations and find their y-value, and see if D or E corresponds to what you get.</p>
<p>I’m really hoping the exam has a question like #4 on 2008 Form B. Part B of that question asks for you to discuss which type of error is more serious in context, Type I or Type II. In the scoring guidelines it says a case can be made for either side, since it is open to interpretation. It doesn’t get any easier than neither answer being wrong…</p>
<p>The answer is B but i keep on getting .48 from normalcdf(11, infinity, 10.2, 16)
What am i doing wrong?</p>
<p>the sample standard deviation is the true standard deviation/sqrt sample size(or 144)
you take the observed sample mean and standardize it by subtracting by the population mean and then dividing by the calculated sample standard dev. this should give you a value of .6 if u use a z chart, .6 corresponds to a probability of .7257. but since you’re caluclating greater than, you have to subract that from 1, which gives you b.</p>
<p>is barron’s multiple choice supposed to be a lot harder than the actual ap exam?</p>
<p>^Yes, Barron’s is harder than the actual exam.</p>
<p>what are the combinations for the Y? And how do you find the corresponding probabilities? Also cody can you look at questions 23, 19, and 17. Thanks a lot.</p>
<p>^ i’ll send you a PM in about 10 mins, no prob.</p>
<p>EDIT: nevermind… i’m clueless on 17, 19, 23.</p>
<p>just how much harder is the barron’s mc than the actual exam? i’m really frustrated because i keep missing around 11-13 on the barrons mc exams…</p>
<p>hey guys…does anybody have the 2007 MC exam? because I was wondering if somebody could help me with a few questions</p>
<p>Thanks! :)</p>
<p>Anyone have the 1997 exam? :D</p>