It is crucial that the variance of a production process be less than or equal to 25. A sample of 22 is taken. The sample variance equaled 26.
a. Construct a 90% confidence interval for the population variance.
b. Construct a 90% confidence interval for the population standard deviation.
c. State the null and alternative hypotheses to be tested.
d. Compute the test statistic.
e. The null hypothesis is to be tested at the 10% level of significance. Using the critical value approach, state the decision rule for the test.
f. What do you conclude about the population variance?