Understanding z-score

Z-score refers to the standard deviations the element is away from the mean.

It is given by the following formula:

Here X represents the value of the element, σ is the standard deviation, and μ is the population mean.

Interpreting z-scores

• z-score<0: The element is less than the mean

• z-score>0: The element is greater than the mean

• z-score=0: The element is equal to the mean

• z-score=0.5: The element is 0.5 SD greater than the mean

In Julia, it is implemented as follows:

julia> zscore(X,  μ, σ) 

μ and σ are optional as they can be calculated by the function.