Question

Most sports injuries are immediate and obvious, like a broken leg. However, some can be more subtle, like the neurological damage that may occur when soccer players repeatedly head a soccer ball. To examine effects of repeated heading, McAllister et al. (2013) examined a group of football and ice hockey players and a group of athletes in noncontact sports before and shortly after the season. The dependent variable was performance on a conceptual thinking task. Following are hypothetical data from an independent-measures study similar to the one by McAllister et al. The researchers measured conceptual thinking for contact and noncontact athletes at the beginning of their first season and for separate groups of athletes at the end of their second seasorn Factor A: Factor B: Time Sport Before the First Season After the Second Seasonn n 20 n20 Contact T= 180 SS = 380 n 20 T = 80 SS 390 n = 20 Noncontact T= 180 T 160 SS = 350 SS400 ZX2 6,360 Use a two-factor ANOVA with α = .05 to evaluate the main effects and interaction. Source df MS Between treatments Ax B Within treatments Total 80 180 80 1,520 1,860 80 180 80 20 4.000 9.000 4.000 76 79

Answer 1