Convert X to Z Calculator


x =

Average (μ) =

Standard deviation (σ) =


    

Solution:

z =

Z-Score Formula

The formula to convert x to z is the following:
z = (x - μ) / σ

x : the value being solved for
μ : the average or mean
σ : the standard deviation

Sample z-score problem


Haley received a 92 on a test. The class average is 76 with a standard deviation of 7. What is the z-score?

z = (92 - 76) / 8

The z-score is: 2.2857
What does this mean?

This value means that Haley's 92 is 2.2857 standard deviations from the mean. If she fell within 2 standard deviations to the right and left of the average score she would have been within 95% of the class scores, but because she is slightly over 2 standard deviations, it can be inferred that she did better than 95% of the class.




Additional Pages

StandardDeviationCalculator.net

We offer an easy to use standard deviation calculator with formula, examples, explanation and other related information. Our site is for students, business professionals, or personal use. Input is always welcome (no pun intended!), contact us and we will review your suggestions.