If I wanted the margin of error for the 95% confidence interval to be 1 inch, I should select a simple random sample of size: (assume the population standard deviation = 2.415)

A. 5.

B. 7.

C. 23.

D. 39

We are given with

Confidence interval of 95%. This corresponds to a Z value of 1.96

Margin of error, d = 1 inch

Population standard deviation, σ = 2.415 inch

We can calculate for the sample size using the formula

n = Z² σ² / d²

Substituting,

n = 1.96² (2.415) ² / 1²

n = 22.4 ~ 23