The table shows the test scores and the sleep averages of several students. a. write the least squares regression equation that models the data. let x = hours of sleep and y = test score. b. find the correlation coefficient (r value). explain what this tells you about the association of the data. be sure to describe both the strength and direction in your explanation. c. use the equation to determine the approximate test score of a student who sleeps an average of 8 h a night. show your work.