Pearson r

Pearson r is a measure of Effect Size required for the reporting of both the Mann Whitney U test and Wilcoxon signed rank test.

Formula
$$r = \frac{Z}{\sqrt{N}}$$

Where N is the number of observations

Calculation
It can be calculated as follows:

$$r = \frac{Z}{\sqrt{N}}$$

$$r = \frac{-4.503}{\sqrt{50}}$$

$$r = .64$$