# How is a z-score useful in comparing two different distributions?

Once you have the mean difference between the two distributions ($\overline{X}$) and the standard error SE, then your z-statistic is $z = \frac{\overline{X}}{S E}$. You can use this to calculate a p-value. For example, if $| z |$ > 1.96, then the p-value is <0.05.