Research Quarterly, May 1979, reports on a study of impulses applied to the ball by tennis rackets of various construction. Three measurements on ball impulses were taken on each type of racket. For a Classic (wood) racket, the mean was 2.41 and the standard deviation was 0.02. For a Yamaha (graphite) racket, the mean was 2.22 and the standard deviation was 0.07. Is there evidence of a significant difference between the mean impulses for the two rackets at the 5% significance level?