Chapter 4, Problem 4.40E

Researchers studied a random sample of North Carolina high school students who participated in interscholastic athletics to learn about the risk of lower-extremity injuries (anywhere between hip and toe) for interscholastic athletes (Yang et at., 2005). Of 999 participants in girls’ soccer, 74 experienced lower-extremity injuries. Of 1667 participants in boys’ soccer, 153 experienced lower-extremity injuries.

a. Write null and alternative hypotheses about sex and the risk of a lower-extremity injury while playing interscholastic soccer.

b. For these data, the value of the chi-square statistic is 2.51, and the p-value for the chi-square test is .113. Based on these results, state a conclusion about the two variables in this situation and explain how you came to this conclusion.

c. For each sex separately, calculate the percent of participants who had a lower-extremity injury. Explain how the difference between these percentages is consistent with the conclusion you stated in part (b).