Question

1. You want to create a confidence interval to estimate the average height of college students. You know that the standard deviation of this population is 4 inches. What sample size should you use to get a margin of error of approximately 1 inch?

Answer 1

Solution :

Given that,

Population standard deviation = = 4

Margin of error = E = 1

At 95% confidence level the z is ,

= 1 - 95% = 1 - 0.95 = 0.05

/ 2 = 0.05 / 2 = 0.025

Z_/2 = Z_0.025 = 1.96

sample size = n = (Z_/2* / E) ²

n = (1.96 * 4/ 1)²

n = 61.47

n = 62

Sample size = 62