Maybe I check this as homework, maybe I collect it and grade it....we'll see tomorrow...
- Be sure to show work for 3 and 33
- For both questions where you're asked for the interval--5 and the last question--use your graphing calculator to get the interval....
- AND SHOW THE FORMULA for the interval!
If you were out today we did some classwork--you'll have that as extra homework tomorrow, or you can get the questions below!
Tomorrow we'll wrap up chapter 19; then it's vocab quiz (ch. 19) on Thursday and a short (15 min) math quiz Friday!
Here's the multiple choice homework for tonight:
Here's the multiple choice homework for tonight:
And here's (most of) today's classwork questions:
AP Statistics Classwork: Estimating Population Proportions: Complete each of the problems in the space
provided. Remember to answer each question thoroughly and show all work (where
applicable)
1. New research
finds that 45 percent of undergraduate college students show no significant
improvement in the areas of critical thinking and complex reasoning by the end
of their sophomore year. The study, conducted by Richard Arum, sociology and
education professor at New York University and Jospia Roksa, a sociology
professor at the University of Virginia, tracked more than 2,300 college
students at 24 universities from their freshman year in 2005 through their
senior year.
a.) Show
that a one-proportion z-interval is appropriate. (3 points)
b.) Estimate
the proportion of college students nationwide that show no significant
improvement in the areas of critical thinking and complex reasoning (by the end
of their sophomore year). Use a 99% confidence level. (3 points)
c.) Interpret
your answer from part (a). (4 points)
d.) Explain
the meaning of “99% confidence.” (3 points) (SKIP)
e.) A university spokesman refutes this study and
claims that at least 52% of college students show significant improvement in
critical thinking and complex reasoning. Based on your confidence interval
calculated above, is it plausible that this spokesman is correct? Why or why
not? (3 points)
f.) A
follow up study is planned; the designers must achieve a margin of error of (no
more than) 2%. They plan to use the same (99%) level of confidence. These
statisticians also anticipate that 50% of their sample will show significant
improvement in critical thinking (and 50% will not). How large of a sample
should be used? (3 points)
g.) A
local statistician plans to investigate the proportion of students who show
significant improvement in critical thinking and complex reasoning specifically
at Quinnipiac University. What is a conservative estimate for the margin of
error (assume p-hat = 0.5) if a 95% confidence level and sample of 500 students
are used? (3 points)
2. A
local statistician collected a sample and created a confidence interval to
estimate the proportion of all EHHS students who plan to attend Mr. EHHS. The
resulting 95% confidence interval was (34.5%, 48%).
a. Find the sample statistic, p-hat, and the
margin of error for this sample. (2 points) (BONUS)
b. If
the statisticians used 90% confidence what would happen to… (2 points)
i.
Margin of Error?
ii.
Width of the interval?
c. If
the statisticians increased the sample size, what would happen to… (2 points)
i.
Margin of Error?
ii.
Width of the interval?
