Stats Practice Question

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 95% confidence interval for the true population mean textbook weight.

Give your answers as decimals, to two places <  < 

Answer 1

by the empirical rule, 95% of the population is within 2 standard deviations of the mean

55 + or - 2(9.2) = 55+ or - 18.4 = (36.6,73.4)

95% of the population falls between 36.6 and 73.4 ounces