Answer the following:
A
nurse in a large university (N = 30, 000) is concerned about
students' eye health. She takes a random sample of 75 students who
don't wear glasses and finds 27 that need glasses.
A)
Using your graphing calculator, find a 95% confidence interval for
the proportion of students who need to wear glasses but don't.
(Show all work, functions, and inputs on your calculator too)
B)
The nurse wants to be able to estimate, with a 95% confidence
interval and a margin of error of 6%, the proportion of students
who need to wear glasses but don't. Find the necessary sample size
(n) for this estimate.
C)
The following school year, the nurse wants to construct the same
95% confidence interval for the proportion of students who need
glasses but don't wear them, but she thinks the proportion has
changed since last year. Without using the point estimate of the
population proportion from the previous year, find the necessary
sample size (n) for a 95% confidence interval for the population
proportion with a margin of error (m) of 6%.
Thanks.