To combat reduced offense in college baseball, NCAA officials introduced a modified version of the baseball for the 2015 season.The new version has slightly flatter seams, which reduces the amount of drag as the ball flies through the air. Presumably, this should increase the number of home runs hit. To make a fair comparison, let's compare home run rates from the College World Series in 2014 (with the old balls) and 2015 (with the new balls). Both series were played in the same stadium in relatively the same conditions. In 2014, only 3 home runs were hit in 1065 at-bats. In 2015, 15 home runs were hit in 1035 at-bats.

1. Is there convincing evidence that the modified baseball increases the number of home run hits?
2. The difference in home run percentage was small, but the evidence was convincing?
3. Why do you think that the evidence was convincing even though the difference in percentages was so small?
4. Based on the results, should you conclude that the increase in home run percentage was caused by the change in the baseball? Explain.