A Machine Produces Pipes Used in Airplanes

Essay

A machine produces pipes used in airplanes. The average length of the pipe is 16 inches. The acceptable variance for the length is .3 inches. A sample of 25 pipes was taken. The average length in the sample was 15.95 inches with a variance of .4 inches.
a.Construct a 95% confidence interval for the population variance.
b.State the null and alternative hypotheses to be tested.
c.Compute the test statistic.
d.The null hypothesis is to be tested at the 5% level of significance. State the decision rule for the test.
e.What do you conclude about the population variance?