There has been some debate about the effect of aging on the human sex drive. Some writers believe that the sex drive peaks in late adolescence and drops off as the person grows older. Others believe...

There has been some debate about the effect of aging on the human sex drive. Some writers believe that the sex drive peaks in late adolescence and drops off as the person grows older. Others believe that the sex drive increases steadily until it peaks during a person’s 40s. To investigate this, a researcher measures the sex drive of 1 000 people (500 males and 500 females). These subjects fell into three age groups: 19 to 28 years, 29 to 38 years, and 39 to 48 years.

a) Why are the following analyses inappropriate?

• Conducting a one-way ANOVA for all the data to identify differences between the mean sex drive scores for the three age groups.

• Conducting two one-way ANOVAs (one for males and the other for females) to determine whether different age groups differ in sex drive.

b) Draw cell mean plots representing four different possible outcomes. Interpret each plot in words.