Chapter 12.3, Problem 11E

For Exercises 9 through 15, perform these steps. Assume that all variables are normally or approximately normally distributed, that the samples are independent, and that the population variances are equal.

a. State the hypotheses.

b. Find the critical value for each F test.

c. Complete the summary table and find the test value.

d. Make the decision.

e. Summarize the results. (Draw a graph of the cell means if necessary.)

11. Environmentally Friendly Air Freshener As a new type of environmentally friendly, natural air freshener is being developed, it is tested to see whether the effects of temperature and humidity affect the length of time that the scent is effective. The numbers of days that the air freshener had a significant level of scent are listed below for two temperature and humidity levels. Can an interaction between the two factors be concluded? Is there a difference in mean length of effectiveness with respect to humidity? With respect to temperature? Use a = 0.05.

	Temperature 1	Temperature 2
Humidity 1	35, 25, 26	35, 31, 37
Humidity 2	28, 22, 21	23, 19, 18