This project is best carried out if you have access to a computer and statistical software because the calculations for the regressions are rather long.

Collect men’s and women’s heights and weights, from samples of 30 men and 30 women.

a) Which variable is best to use for the IV? Why?

b) What is the correlation coefficient, r, for men’s heights and weights? For women’s?

c) Can you write the regression equation for each sex separately?

d) What did you find? How would you explain it? If you are working with classmates, compare your findings to theirs.

If you found a major difference between the correlations, notice that this could be considered an example of an interaction effect: The height-weight relationship is different for different values of the variable gender (in this instance, men and women). We will discuss interaction effects further in Chapter Eleven.