In order to compare the durability of four different brands of golf balls (ALPHA, BEST, CENTURY, and DIVOT), the National Golf Association randomly selects balls of each brand and places each ball into a machine that exerts the force produced by a 250-yard drive. The number of simulated drives needed to crack or chip each ball is recorded. Use a significance level of 0.05 to conduct all hypothesis tests and construct confidence intervals.

Select the correct null hypothesis.

Analysis of Variance Sum of Source DF Squares Mean Square F Ratio Prob > F BRAND 3 38504.150 12834.7 21.1742 <.0001 error c. total>