Eight students, randomly selected from a large class, were asked to keep a record of the hours they spent studying before their final exam. The following table gives the number of hours they studied...

What is the value of r?

a) 0.6802

b) 0.6208

c) 0.6280

d) 0.6820

Extracted text: Eight students, randomly selected from a large class, were asked to keep a record of the hours they spent studying before their final exam. The following table gives the number of hours they studied before the finals and their scores on the final exam. Number of Final exam Student hours XY score (y) x2 Y2 (x) 1 15 97 1455 225 9409 7 78 546 49 6084 3 12 87 1044 144 7569 4 92 736 64 8464 18 89 1602 324 7921 6. 57 342 36 3249 7 74 666 81 5476 8 11 70 770 121 4900 Total 86 644 7161 1044 53072