How to Calculate a Standard Score

Use the standard score to help you curve test scores.
••• calculator image by Henryk Olszewski from Fotolia.com

Standard score is a statistics term. The standard score shows how far away from the mean a score falls. It is also known as a z-score. Using a z-score table, you can find where the score falls on the table and figure out what percentile the score falls in. This is a way of standardizing tests in order to curve the scores to fit around the mean. If everyone does poorly on a test, the score distribution will curve up to fit around the average score on the test.

    Find the mean and standard deviation of your data set. For example, assume you have a data set with a mean of 24 and a standard deviation of 5. You want to find the standard score of 28 in the data set.

    Subtract the mean from the data for which you want a standard score. In the example, 28 minus 24 equals 4.

    Divide the difference between the data and the mean by the standard deviation. In the example, 4 divided by 5 equals a standard score of 0.8. You can use this score on a z table to see where it falls as a percentage of the rest of the scores.

    Things You'll Need

    • Data set
    • Mean of data set
    • Standard deviation of data set

Related Articles

How to Read a Bell Curve
How to Find Standard Deviation on a TI 84 Plus
How to Approximate the Mean of Group Data
How to Grade Using a Square Root Curve
Test Your Knowledge on Middle School Science
How to Report Z-Score Results
How to Calculate Average Deviation From the Mean
How to Calculate Percentage of Non Overlapping Data...
How to Calculate CV Values
How to Convert T-Scores to Percentiles
How to Calculate Statistical Mean
How to Calculate Stanine Scores
Characteristics of Aquatic Plants
How Do I Calculate the Relative Standard Deviation...
How Good Is a 400 on the Math Part of the SAT?
How to Calculate Standard Errors
How to Calculate a P-Value
How to Find Z-Scores on a TI-84 Plus
How to Solve for Range
How to Read a Bell Curve

Dont Go!

We Have More Great Sciencing Articles!