Suppose a golf association wants to compare the mean distances associated with four brands of golf balls when struck by a driver. Ten balls of each brand are used in the experiment. The experiment randomly selects 40 golfers and then randomly assigns 10 golfers to each of the four brands. Each golfer then strike the ball of the assigned brand once, and the distances are recorded in the table below:-

Brand A Brand B Brand C Brand D

143.5 141.4 152.7 161.1

161.8 161.2 167.5 157.1

142.4 134.7 171.2 154.8

138.9 157.4 174.3 150.6

141.5 146.9 137.9 154.9

144.3 151.5 147 158.6

144.4 130.6 149.6 142.4

151.8 138.9 169.8 169.4

148 162.1 146.3 157.3

155.9 172.1 159.7 150

1. From this data, is any difference between the mean distances associated with the four brands of golf balls when struck by a driver? Use a 10% significance level for the test.

Write down the five steps of hypothesis testing (round to two decimal places).

2. What is the major drawback of this experiment design? If you are designing the experiment, what would you do?