A study of 80 white mice showed that their average weight wa

A study of 80 white mice showed that their average weight was 3.7 ounces. The standard deviation of the population is 0.6 ounces. Which of the following is the 95% confidence interval for the mean weight per white mouse?

Solution

Given a=1-0.95= 0.05, Z(0.025) = 1.96 (from standard noraml table)

So the lower bound is

xbar - Z*s/vn=3.7 -1.96*0.6/sqrt(80) =3.568519

So the uppepr bound is

xbar +Z*s/vn=3.7 +1.96*0.6/sqrt(80) =3.831481