# Worksheet for how to find out Z Score Value

A key point is that calculating z requires the population mean and the population standard deviation, not the sample mean or sample deviation. If you have set of data then you have to calculate standard deviation. It requires knowing the population parameters. A common name for standard score is the z-score and often used in statistics. This worksheet can help you to understand how to calculate the Z score value. The formula used to calculate Z-score is,
The Standard Score can be calculated from the following formula

where
x is a raw score to be standardized
µ is the mean of the population
σ is the standard deviation of the population

Example:
Find the standard score for given Random value is 9, sample mean is 5, sample standard deviation is 6
Given: X = 9, µ = 5, σ = 6

Substitute these values in the above formula,
Z = (9 - 5)/6
= 4/6
= 0.6667

The z value is 0.6667

When you try such calculations on your own, this z score calculator can be used to verify your results of calculations.