Calculate the value of the product-moment correlation coefficient for the following. Check using a calculator in LR mode if possible. Comment on your answers.

(a) x 10 15 201 25 4 y 4.3 5.9 6.9 6.5 8.2

(b) x 12 14 16 18 20 22 y 100 70 86 49 60 50

(c) 1 2 3 4 5 6 7 8 12.4 12.8 12.6 13.9 13.4 13.2 14 14.6

(d) t 27 43 62 89 72 z 48 50 81 75 60