A researcher at the Medical College of Virginia conducted a study of 60 randomly selected male soccer players and concluded that frequently “heading” the ball in soccer lowers players’ IQs (USA Today, August 14, 1995). The soccer players were divided into two groups, based on whether they averaged 10 or more headers per game. Mean IQs were reported in the article, but the sample sizes and standard deviations were not given.

Suppose that these values were as given in the accompanying table.

n Sample Mean Sample sd Fewer Than 10 Headers 35 112 10 10 or More Headers 25 103 8 Do these data support the researcher’s conclusion? Test the relevant hypotheses using a .05. Can you conclude that heading the ball causes lower IQ?