Question

The following data gives the number of hours 77 students spent studying and their corresponding grades on their midterm exams.

Hours Spent Studying	0.5	1	2.5	4	4.5	5.5	6
Midterm Grades	60	63	72	81	84	90	99

Copy Data

Step 1 of 3 :  

Calculate the correlation coefficient, r. Round your answer to six decimal places.

Answer 1

Step 1:

X Values
∑ = 24
Mean = 3.429
∑(X - M_x)² = SS_x = 27.714

Y Values
∑ = 549
Mean = 78.429
∑(Y - M_y)² = SS_y = 1213.714

X and Y Combined
N = 7
∑(X - M_x)(Y - M_y) = 181.714

R Calculation
r = ∑((X - M_y)(Y - M_x)) / √((SS_x)(SS_y))

r = 181.714 / √((27.714)(1213.714)) = 0.990784