Whenever we are comparing two different data sets, we must be careful and make sure that the data has been appropriately standardized in order to make the comparison valid.

Data values coming from two distributions with different mean and variance can be compared by computing their respective Z scores. The Z score for any given data point can be calculated using the formula,

*Z*=*X*−*μ*/*σ*.

Here, *μ* denotes the mean of the distribution and *σ* denotes the variance.

The compare Z scores calculator below computes the Z scores for the two given data points allowing us to make comparisons between these two data values.

z-score of first value = (19–15) / 4.2 = **0.9524**

z-score of second value = (17–14) / 2.6 = **1.1538**