# Once you have a z-score, how do you calculate the value that is found in the z-tables?

Dec 15, 2017

The Z-score value is the distance between the raw score or an individual member to the population mean in terms of Standard Deviations.

#### Explanation:

A standard normal table , also called the unit normal table or Z table , is a mathematical table for the values of Φ , which are the values of the cumulative distribution function of the normal distribution (that's why we use the precalculated tables instead of generating them each time).

Actual formula:
f(x, μ, σ2) = 1/(σ^2π)√exp((−1/2)((x−μ)/σ)^2)
http://math.tutorvista.com/statistics/z-score-table.html

https://www.mathsisfun.com/data/standard-normal-distribution-table.html

Here's a couple of good guides:
https://www.easycalculation.com/statistics/z-score-standard.php
(read below the calculator for the description).

https://ncalculators.com/statistics/z-score-calculator.htm