Professor Richard Head of Publish or Perish State University is examining the effect of the publication of a book on faculty salaries. Book publication is a dummy variable coded 0 if a professor has not published a book and 1 if he or she has published a book (X). Faculty salaries (Y) in dollars have been regressed on this variable, yielding the following results:
Ŷ = 34,132 + 5618X
r2 = .40 Sy|x = 2,326 sb = 2050 n = 87
Based on these results, what is the average salary of professors who have not published a book? Of professors who have published a book? Is the difference statistically significant? If Dr. Head wanted to increase his salary, what would you recommend as a course of action?