Question

A research company desires to know the mean consumption of milk per week among males over age 45. They believe that the milk consumption has a mean of 4.5 liters, and want to construct a 95% confidence interval with a maximum error of 0.10 liters. Assuming a standard deviation of 1.5 liters, what is the minimum number of males over age 45 they must include in their sample

Answer 1

Solution :

Given that,

Population standard deviation = = 1.5

Margin of error = E = 0.10

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 * 1.5 / 0.10)²

n = 864.36

n = 865

he minimum number of males over age 45 is 865