How to Get Excel to Calculate Uncertainty

Calculating the uncertainty of a statistical value is helpful in a range of business applications such as evaluating customer feedback, testing the quality of assembly line products and analyzing historical returns on a stock. Given a sample size of data, the standard deviation will tell you how much variation within the sample there is from the average. Uncertainty arises from the size of the sample size and from which members of the population you happen to be including. With Microsoft Excel, you can measure the uncertainty of the sample's standard deviation by calculating the standard error of the mean.

Open your spreadsheet in Excel.

Enter the values for your sample size, one per cell, in an empty column. For example, enter the values "2," "4," "6," "8" and "10" (omit the quotation marks here and throughout) in the cells A1, A2, A3, A4 and A5.

Calculate the sample standard deviation by clicking an empty cell, such as B1, and typing "=STDEV.S(A1:A5)." Replace "A1:A5" with the range of cells containing the values for your sample. Using the previous example, the standard deviation of the sample size is 3.16.

Calculate the standard error of the mean by clicking an empty cell and typing "=B1/SQRT(COUNT(A1:A5))." Replace "A1:A5" with the range of cells containing the values for your sample. Replace "B1" with the cell containing the standard deviation calculation from the previous step. Using the previous example, the standard error of the sample is 1.41.