Question

Question 1. use the above survey results to construct a 95% confidence interval for the proportion p of all ohio state university female students who would be willing to walk somewhere after dark that they would normally not go if they had a cell phone.

Answer 1

za/2 = invnorm(.975,0,1) = 1.96

confidence interval:

.42 +/- 1.96*square root of ((.42)(1-.42)/305)

.42 +/- .05539

(.42 - .05539, .42 + .05539

(.36461, .47539)

Lower bound: .365 (rounded to 3 decimals)

Upper bound: .475 (rounded to 3 decimals)