1. Open your workbook in the Excel 2007 application.
2. Determine the cell addresses of your data array. For example, if your data is contained in the first 20 rows of column A, your cell addresses are A1:A20.
3. Click a blank cell and type the following formula: =(STDEV(A1:A20)/AVERAGE(A1:A20))Substitute the address of your data array in place of A1:A20 in the above example.
4. Press 'Enter.' Excel divides the standard deviation of the array by the average value of the array. The result of this calculation is the array's coefficient of variation, which is displayed in the cell.