Question

You measure 47 textbooks' weights, and find they have a mean weight of 55 ounces. Assume the population standard deviation is 9.2 ounces. Based on this, construct a 99% confidence interval for the true population mean textbook weight.

Give your answers as decimals, to two places

_____________<u<__________________

Answer 1

Solution :

Given that,

Sample size = n = 47

Z/2 = Z0.005 = 2.576

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

= 2.576 * (9.2 / 47)

Margin of error = E = 3.46

At 99% confidence interval estimate of the population mean is,

- E < < + E

55 - 3.46 < < 55 + 3.46

51.54 < < 58.46

( 51.54,58.46) , 51.54 < < 58.46