3. A recent study concerning knee injuries of football players compared two types of football shoes. Out of a randomly chosen group of 1440 players, 240 used multicleated shoes and 1200 used more...

Extracted text: 3. A recent study concerning knee injuries of football players compared two types of football shoes. Out of a randomly chosen group of 1440 players, 240 used multicleated shoes and 1200 used more conventional football shoes. All played on natural grass. Of those using the multicleated shoes, 13 suffered knee injuries. Of those using conventional shoes, 78 suffered knee injuries. (a) Test the hypothesis that the probability of a knee injury is the same for both groups of players. Use the 5 percent level of significance. (b) Are the given data strong enough to establish that the multicleated shoes are superior to the conventional ones in terms of reducing the probability of a knee injury? (c) In part (b), at what levels of significance would the evidence be strong enough?