Remember the Little League instructional video discussed in Chapter 23? Ads claimed it would improve the performances of Little League pitchers. To test this claim, 20 Little Leaguers threw 50 pitches each, and we recorded the number of strikes. After the players participated in the training program, we repeated the test. The table shows the number of strikes each player threw before and after the training. A test of paired differences failed to show that this training improves ability to throw strikes. Is there any evidence that the effectiveness of the video (After - Before) depends on the player's initial ability to throw strikes (Before)? Test an appropriate hypothesis and state your conclusion. Propose an explanation for what you find.

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Number of Strikes (out of 50) Before After Before After 28 29 30 32 34 32 35 36 33 35 32 28 32 30 32 31 32 34 32 35 34 35 34 36 37 36 37 35 32 32 36 37 32