Refer to Exercise 14.10. Suppose that the experiment is redone in the following way. Thirty taxpayers fill out each of the four forms. However, 10 taxpayers in each group are in the lowest income bracket, 10 are in the next income bracket, and the remaining 10 are in the highest bracket. The amount of time needed to complete the returns is recorded.

Column 1: Group number

Column 2: Times to complete form 1 (first 10 rows = low income, next 10 rows = next income bracket, and last 10 rows = highest bracket)

Column 3: Times to complete form 2 (same format as column 2)

Column 4: Times to complete form 3 (same format as column 2)

Column 5: Times to complete form 4 (same format as column 2)

a. How many treatments are there in this experiment?

b. How many factors are there? What are they?

c. What are the levels of each factor?

d. Is there evidence at the 5% significance level of interaction between the two factors?

e. Can we conclude at the 5% significance level that differences exist between the four forms?

f. Can we conclude at the 5% significance level that taxpayers in different brackets require different amounts of time to complete their tax forms?