Question

weights of women in one age group are normally distributed with a standard deviation of 10bounce. A researcher wishes to estimate the weight of all women in this age group. Find how large a sample must be drawn in order to be 90 percent confident that the sample mean will not differ from the population mean by more than 3.4 bounce

Answer 1

Margin of error, E = Z*

Here, E = 3.4

= 10

For 90% confidence level, Z* = 1.645

3.4 = 1.645 x

= 4.838

n = 24 (rounded up)

Sample size required to be 90 percent confident that the sample mean will not differ from the population mean by more than 3.4 = 24