Redshifts of quasi-stellar objects. Refer to the Journal of Astrophysics & Astronomy (Mar./Jun. 2003) study of redshifts in quasi-stellar objects presented in Exercise 11.27 LO9 

(p. 627). Recall that simple linear regression was used to model the magnitude (y) of a quasi-stellar object as a function of the redshift level (x). In addition to the least squares line, yn = 18.13 + 6.21x, the coefficient of correlation was determined to be r = .84.

a. Interpret the value of r in the words of the problem.

b. What is the relationship between r and the estimated slope of the line?

c. Find and interpret the value of r 2.