Inference for proportions: confidence intervals

Question 1

what is p?

Answer 1

an unknown parameter that we want to make inferences about

Question 2

confidence interval for proportion

Answer 2

use approximate normality for equations. If n is larger than 80, you can use p hat instead of p

there is also a conservative estimate which is p hat +/- 1/square root(n)

Question 3

sample size for estimating proportions

Answer 3

n = p(1-p)(Za/2/d)^2

If p is not known use 0.5 to get the max value