i know the correlation is r=0.14286 but i am not sure how to do the steps to get that answer can someone help me?

To find out how uniformly babies grow, we measured the weights of random eight babies first at 11 months and then at 27 months. We obtained the following data.

Weight at 11 months Weight at 27 months

14 25

14 28

20 26

17 24

15 22

17 27

15 23

16 25

Evaluate the correlation coefficient and describe the correlation.