Question

A sample of 31 IQ scores are selected from 100 IQ scores. Those scores produce a mean and population standard deviation of 132 and 10, respectively. Find the 95% confidence interval for the annual average of IQ scores.

Answer 1

Solution :

Given that,

Sample size = n = 31

Z/2 = 1.96

Margin of error = E = Z/2* ( /n)

= 1.96 * ( 10/ 31)

Margin of error = E = 3.52

At 95% confidence interval estimate of the population mean is,

- E < < + E

132 - 3.52 < < 132 + 3.52

128.48 < < 135.52

(128.48 , 135.52)