Question

The sample size needed to provide a margin of error of 2 or less with a .95 probability when the population standard deviation equals 13 is

Group of answer choices

163

13

162

161

Answer 1

Solution :

Given that,

Population standard deviation = = 13

Margin of error = E = 2

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 * 13/ 2)²

n = 162.31

n = 163

Sample size = 163