The STDEV function (which stands for standard deviation) will return a measure of how widely the values are dispersed from the average value (the mean). Calculating the standard deviation can be quite useful when you are assessing test scores and student performance. SD helps you see how a set of student scores varies from around the mean. In other words, you can see whether the student has performed consistently on their exams or have major inconsistencies.

The syntax for the STDEV function is:

=STDEV(first value, second value, etc.)

For instance, if we have the following data set given above, the STDEV function for Frank's set of scores would be:

=STDEV(B4:E4)

To perform an STDEV function like the example above, follow the steps below:

• Click in the cell that you want the STDEV to be performed (in the above example that will be cell F4).
• Click on the fx button (function button) in the top toolbar.
• Select the Statistical category and click on STDEV in the Function name area.

• Click on the OK button.
• Excel will automatically assume you want to average a certain row of cells or columns. If this is the row or column you want averaged, click the OK button. If not, click and drag across the cells you want to include in the average and click OK.

• The STDEV score of the range of cells should now appear in the designated cell (in this example "82.4" is shown in cell F4).