<p>I used the binomial formula to find this out.</p>
<p>i didnt write out hypothesis…
but i did figure out the part that because zero is in the interval 
s;ldkjfasdf;lk shoot.</p>
<p>u don’t need a hypothesis when ur calculating an interval.<br>
Or are you talking about something else?</p>
<p>oh…
Totally didn’t realize that I was suppose to use the 70th percentile thing in part a.</p>
<p>*****! i put x2 goodness of fit. but its definitely independence.</p>
<p>Wat test should we have used for question number 1? i put chi-Square test for homogeneity. : /</p>
<p>Definitely chi-square test of independence. :]
Also for 1a, I used a segmented bar graph.</p>
<p>Yea you use binomcdf for the 2 out of 5 cars thing.
I wrote it out in formula format…I think I messed it up but the final answer is still right.</p>
<p>Last part of the first one definitely is Chi-Square Independence/Association.</p>
<p>And wow, half the people I asked put Type II and the other half put Type I, lol. They have their reasoning and it doesn’t seem to make complete sense. I put down Type I, remember they asked which error COULD HAVE BEEN committed, not which error was committed (there wasn’t any error at all…).
I might’ve messed that one up aswell.</p>
<p>oh crap : ( I get it. Hopefully they give partial credit b/c i put in “chi-square” test </p>
<p>I used a double bar graph for graph</p>
<p>i’ll be EXTREMELY disapointed if i make less than a 5 after having made a raw score of 82/100 on the 2008 practice exam we took in class</p>
<p>I hope the curve is generous, but the questions weren’t that bad, so I think it will be harsh. =/</p>
<p>Do they give partial credit? Like a 3.5? lol.</p>
<p>
[QUOTE=alicimoo]
I hope the curve is generous, but the questions weren’t that bad, so I think it will be harsh. =/
[/quote]
</p>
<p>It won’t be too generous, thats for sure.
This was the easiest #6 in years…compare this to the #6 of 2006 Form A, lol. We’ve done harder ones in-class and we were all freaking out that this year’s #6 will be something crazy. Instead, we get a pretty easy one (relative to all previous AP Stat tests).</p>
<p>yeah, i nailed all of question one, cept i called in chi-square of homogeneity…
oh well</p>
<p>For 2b, don’t you have to justify the use of a binomial setting before proceeding to calculate the binomial probability? Like: "Using a binomial setting where success will be defined as ‘car stops over the 70th percentile stopping distance’. Because the cars are selected randomly, and we set the number of cars to be selected randomly at 5, we can assure independence of cars, and the same probability for each ‘n’.</p>
<p>Lol at Form B’s #6.
I can imagine people easily getting confused by that, but I know how to do it even though I suck at probability. Its all confidence intervals.</p>
<p>how do you justify the use of a binomial setting?</p>
<p>I mean its pretty self-explanatory. If there is a set number of "choosings’ (in this case 5), then a binomial calculation should be done.</p>
<p>^ It didn’t ask to justify it, did it?
If you were to, you would say:
- Only two possible outcomes per trial.
- Constant probability of successes per trial.
- Fixed number of trials.
- All trials are independent of each other.</p>
<p>
I didn’t do any practice tests…or even look at them. My teacher doesn’t …teach. The whole year, he just told us to read the book, gave us odd problems to do in the book because they had the answers in the back, then gave us lots and lots of worksheets…</p>
<p>Still hoping for a 5, hoping for at least a 4 though.</p>
<p>I’m pretty sure chi-square test for homogeneity is the same thing as the test for independence (thats what it says in my class notes). I’m not sure you have to justify the use of a binomial setting, from previous part II questions only an algebraic justification was necessary, that is plugging it into the formula.</p>
<p>On 2b, one had to use 1 - binomcdf (5, 0.3, 2) since the question asked for the probability that ATLEAST 2 cars out of 5 randomly selected cars in the study will stop. Binomcdf just does AT MOST (less than or equal to), so AT LEAST is the complement of at most, hence the 1 - binomcdf.</p>
<p>at least i think so. lol</p>
<p>aw we can’t just write “chi-square test”??
i didn’t know anything cuz my teacher’s teaching the last 5 chapters AFTER the AP…-__-</p>