Question

Suppose a randomly selected sample of n = 62 men has a mean foot length of x = 28 cm, and the standard deviation of the sample is 3 cm. Calculate an approximate 95% confidence interval for the mean foot length of men. (Round the answers to one decimal place.)
to cm

Answer 1

Solution :

Given that,

sample size = n = 62

Degrees of freedom = df = n - 1 = 62 - 1 = 61

t _/2,df = 2.000

Margin of error = E = t_/2,df * (s /n)

= 2.000 * ( 3/ 62)

= 0.8

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

- E < < + E

28 - 0.8 < < 28 + 0.8

27.2 < < 28.8

95% confidence interval for the mean: (27.2 , 28.8)