Florida State University information scientists assessed the impact of online courses on student performance (Educational Technology & Society, Jan. 2005). Each in a sample of 24 graduate students enrolled in an online advanced Web application course was asked, "How many courses per semester (on average) do you take online?" Each student's performance on weekly quizzes was also recorded. The information scientists found that the number of online courses and the weekly quiz grade were negatively correlated at r = -.726.

a. Give a practical interpretation of r.

b. The researchers concluded that there was a "significant negative correlation" between the number of online courses and the weekly quiz grade. Do you agree?