The article "Softball Sliding Injuries" (American Journal of Diseases of Children [1988]: 715-716) provided a comparison of breakaway bases (designed to reduce injuries) and stationary bases. Consider the accompanying data (which agree with summary values given in the paper).
a. Is the proportion of games with a player suffering a sliding injury significantly lower for games using breakaway bases? Answer by performing a level .01 test.
b. What did you have to assume in order for your conclusion to be valid? Do you think it is likely that this assumption was satisfied in this study?