In promiscuous species of mammals, such as deer mouse, the breeding success of males can be predicted from their testes size and the number of sperm they produce. Fisher et al. (2018) investigated whether testes size could be affected by the intrauterine environment of fetal mice. In particular, they examined whether the number of male littermates could predict male testes size. (Such an association might occur, for example, if many males in a litter generated a higher-testosterone environment for all developing embryos.) The data are shown in the figure below along with some summary statistics. The full data set is on the book’s website.

a. Do these data fit the assumptions of linear regression well? Explain.

b. Give the best-fitting line predicting testes area from the number of male littermates.

c. Do these data provide sufficient evidence that testes area is predictable from the number of male littermates?

Transcribed Image Text:

ΣΧ=513 ΣΥ=9020 n=300Σ x = 513 ΣΥ = 9020 n = i 300 Σ Χ2=1291 ΣΥ2=283,936.3 ΣΧΥ=16,030.93 x = 1291 Σγ = 283,936.3 ΣXY = 16,030.93