Female college student participation in athletics has increased dramatically over the past few decades. Sports medicine providers are aware of some unique health concerns of athletic women, including disordered eating. A study compared disordered-eating symptoms and their causes for collegiate female athletes (in lean and nonlean sports) and nonathletes. The sample mean of the body dissatisfaction assessment score was 13.1 (S=7.8) for 17 lean sports athletes (those sports that place value on leanness, including distance running, swimming, and gymnastics) and /1 (S= 5.8) for the 68 nonlean athletes. Assume equal population standard deviations. Complete parts a and D below.

a. find the standard error for comparing means