Z-score Calculator

The Z-score calculator is used to compute the Z-score by taking inputs of row score, population mean, and standard deviation.

Related Z Table Mean Calculator Variance Calculator

How to Use the Z-score Calculator?

Follow these simple steps below:

  1. Firstly, input the row score (x), population mean (μ), and standard deviation (σ).
  2. After entering all the values, click the 'Calculate' button and the Z-score will be displayed on your screen.
  3. Press the 'Reset' button for the new calculations.

What is Z-score?

The Z-score defines the difference between the data points of raw scores from the mean value. You can get the number of standard deviations of a data point above the mean value. It's also known as the Standard Score, Normal Score, or Z-value.

Types of Z-score:

  • Positive Z-score: When the data point lies above the mean, the Z-score is positive.
  • Negative Z-score: When the data point lies below the mean, the Z-score is negative.

How to Calculate the Z-score?

The formula to calculate the Z-score is:

Z =  
(x - μ)
σ

Here,
Z = Z-score,
x = Raw Score,
μ = Mean,
σ = Standard Deviation.

Let's take an example.

Example:

Calculate the z-score for the following values:

Raw score, x = 20,
Mean, μ = 15,
Standard Deviation, σ = 5.

Let's put the above values in the formula and evaluate it.

Z =  
(x - μ)
σ
=  
(20 - 15)
5
=  
5
5

= 1

Finally, the Z-score = 1.