Compute SP (the sum of products of deviations) for the following scores. Note: Both means are decimal values, so the computational formula works well:
X Y
1 4
4 3
5 9
0 2
a. Compute the Pearson correlation.
b. With a small sample, a single point can have a large effect on the magnitude of the correlation. Change the score X = 5 to X = 0 and compute the Pearson correlation again. You should find that the change has a dramatic effect on the value of the correlation.