How to Find the Z-Score Using Microsoft Excel

A Z-score, used in statistics, is the measurement of the number of standard deviations a number is above or below a mean. Z-scores are sometimes referred to as "standard scores" and "Z-values." The Z-score is most often compared to samples to the standard normal deviate to determine how a set of data compares to standard numbers. The Z-score can be calculated by subtracting the mean from the raw score and dividing by the standard deviation. However, the Z-score can also be calculated using a function in Microsoft Excel.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Set of data

1. Open an Excel spreadsheet and enter your data in one column. Be sure to enter each piece of data for accurate results.

2. Click any empty cell to place the result in. Click the "fx" button on the formula bar to open the "Function" window.

3. Enter the number you wish to calculate the Z-score for in the "X" box. Enter a number or a cell reference where the number is located, such as "A5."

4. Enter the mean in the "Mean" box. If you do not know your mean, use the "AVERAGE" function to calculate the mean. For instance, if all your data was in Column A, enter something similar to "AVERAGE (A2:A15)." The "A2:A15" is your range of cells. This range varies greatly, depending on the row you use and the number of numbers you enter.

5. Enter your standard deviation in the "Standard_dev" box. Calculate your standard deviation through Excel by typing "STDEV" along with your range as illustrated in Step 4.

6. Press "OK" to display the result in the cell you chose in Step 2.

Tips & Warnings

• View the results of the formulas used in Step 4 and Step 5 beside their respective text boxes.
• Double check that you have the correct amount of numbers listed in your column or your Z-score will be incorrect.

References

• American.edu: Use Excel to Determine a Z-score