How to Use Excel to Find the Critical T-Value

A "t table" is also known as the "Student's t Table." A critical value is the value that a test value must be greater than to reject the null hypothesis. The critical value can be looked up manually in a t-table distribution. However, it would be relatively quicker to simply use the Data Analysis toolpack in Microsoft Excel. Simply enter the data in Excel and launch the Data Analysis tool. After filling in the range details, hypothesized mean and alpha value, the results will be displayed in the output cell that was selected.

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Step

Enter data in two columns with the results. For example, a company chooses a sample of ten regions and wants to compare sales before and after a new product has been introduced. The sales data before the product launch would be entered in cells A2 through A11 and the after sales data would be entered in cells B2 through B11. Place the appropriate headings in cells A1 and B1.

Step

Go to the "Data" tab and click on "Data Analysis" under the "Analysis" section. Select "t-Test: Paired Two Sample for Means" and click "OK." See the Tips section on how to add the Data Analysis toolpack if it is not already in the toolbar.

Step

Enter "$A$1:$A$11" in the "Variable 1 Range" field and "$B$1:$B$11" for "Variable 2 Range." Put "0" for the "Hypothesized Mean Difference." Check off "Labels" to indicate that there are column headings in cells A1 and B1. Enter "0.5" for the "Alpha," which is the degrees of freedom.

Step

Select "Output Range" and enter the cell number where you would like the results to be displayed, such as $A$14. Click "OK."

Step

Locate the critical one-tail and critical two-tail t values. In our example, the values are located in cells A25 and A27.