Question

You measure 29 textbooks' weights, and find they have a mean weight of 71 ounces. Assume the population standard deviation is 14.1 ounces. Based on this, construct a 99% confidence interval for the true population mean textbook weight. Give your answers as decimals, to two places.

Answer 1

Solution :

Given that,

Sample size = n = 29

Z_/2 = 2.576

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

= 2.576 * (14.1 / 29)

Margin of error = E = 6.74

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

- E < < + E

71 - 6.74 < < 71 + 6.74

64.26 < < 77.74

(64.26 , 77.74)