Testosterone is a steroid in men that affects sex drive, bone, and muscle mass. Researchers wanted to determine the impact of marriage on testosterone levels in males.

(a) The researchers obtained baseline measures of married and unmarried males in the study. The testosterone levels of both groups are shown in the table below. Does the sample evidence suggest the testosterone levels of the married men are lower than the testosterone levels of the unmarried men at the α  = 0.05 level of significance?

(b) Testosterone levels are known to decline with age. Does the sample evidence suggest the married males are older than unmarried males at the α  = 0.05 level of significance? What do these results suggest about any conclusions drawn in part (a)?

The results of parts (a) and (b) suggest that we cannot simply compare the testosterone levels of married and unmarried males. To determine the role that marriage may play in testosterone levels, the researchers computed the decline in testosterone over a 10-year period. The table below shows the amount of testosterone levels declined among males who transitioned from married to unmarried and the decline in testosterone among males who transitioned from unmarried to married within the 10-year period. Do the results suggest that males who transitioned from unmarried to married experience a greater decline in testosterone levels than those who transitioned from married to unmarried at the α = 0.05 level of significance?

Transcribed Image Text:

X S n Married 20.1 nmol/L. 7.2 1454 Unmarried 22.1 nmol/L 7.5 nmol/L 245