***AP Statistics Thread 2015-2016***

@desiboy1998 Disregard what I wrote above. I meant to say that it would be reasonable to conclude that the failure rate of the super igniters is less than .15. Since it is very unlikely to have 30 successes in a row (I calculated and got .0076) if the failure rate is .15, it would be reasonable to conclude that the success rate is higher than .85 given that 30 successful launches occurred. I’m not sure if I’m interpreting part c correctly…

@XCRat2016 but the question I see is asking for the probability. not the result of significance test.

4 part c is connection to the idea of a significant testing (something is significant because it has a low probability of happening but it occurred anyway)

The first 30 launches being successful has a very small probability (.85^30). That should lead us to believe that the failure rate is actually less than .15

@superbunny320 you are correct

I believe you are also correct with 6a (depending on whether they’re picky about strength)

How did people do #4 part b?

I had (.85^30)(.15) / (.85^30) = .15
And (.85^31)(.15) / (.85^30) = .1275

.15 + .1275 = .2775

@holyground I got the same answer as you for #4 part b.

For part 5 A, I used Z interval. I calculated the SD by sqrting (.37*.63)/1048. Is it wrong? From what I heard people used 1 prop z interval.

Is 4a just 0.85^30 = 0.00763?

For question 5 part © I put no because while a two-sample confidence interval is a confidence interval, while determining whether or not a difference in proportions is significant requires a hypothesis test (i.e. two-sample z-test).

For question 6 (e) I said that for the fields of business, physics, and chemistry, the more semesters of university one takes, the lower their starting salary will be.

@ShinValor i most likely think z interval is wrong because it said specifically to use 1 pop z interval. I mean you might get partial credit who knows

@superbunny320 ya for the rocket question i messed up for that one. I hope i get partial credit tho!

Question 5 Part C, as my teacher said, should have been no, because the samples would need to be independent, which they were not.
Question 4 Part B was something like .85 [insert something here I forgot] .85*.15. I don’t really recall what he said, but it was around the .2 area I think. Or at least had a two in it.
I do recall most of the answers my teacher said-he also works at TCNJ and Princeton University if anyone doubts his credibility- so I can try to help with questions I suppose? ^^

@c0llegeb0und2468 Yes, that would be how to do it.

For question #1 if I never said what the actual mean and median would be with the increase in 18$ and I just said that the mean increses and the median stays the same, would that be fine?

How is each question of the FRQ graded. Like say there is a question but you messed up on like 2 out of 3 parts how many points are taken off?

The scoring guidelines vary for each question; They will be released with the scores in July

Just in case you didn’t hear:

“Nice work: students taking AP Statistics this year demonstrated stronger mastery overall, so there’s a solid increase in the % earning 3+.”

2016 AP Statistics scores: 5: 13.9%; 4: 21.7%; 3: 24.7%; 2: 15.7%; 1: 24%.

I got a 5! YES

I am on the East Coast, and I used Speedify VPN for IOS to get it. ITS AMAZING

Got a 5, yessssssssssssss

Got a 2, somehow I feel like that’s a mistake…I got an A in the class and felt like that test was easier than expected