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Test for one mean


Allows to test the hypothesis that a sample mean is equal to a given prespecified mean (with unknown standard deviation) or certified value.

This test is not performed on data in the spreadsheet, but on statistics you enter in a dialog box.

Required input

The values are entered in the following dialog box:

Test for one mean dialog box

First enter the sample mean, standard deviation and sample size (n) in the dialog box. Next, in the input field Test mean is equal to: enter the value to compare the mean to. As an example, a sample mean of 98 with standard deviation of 2.8 and sample size 8 is compared with the certified value 100.

When all data have been entered, press Enter or click Test.


First the program displays a 95% confidence interval for the mean. Next, the calculated t-value, degrees of freedom and probability (P) are displayed. If the P-value is less than 0.05, then the hypothesis that the mean is equal to the given value is rejected, and the alternative hypothesis that there is a significant difference between the two values can be accepted.

In the example, the P-value is 0.0831 so you do not reject the hypothesis that the sample mean of 98 is equal to 100.

In the Comment input field you can enter a comment or conclusion that will be included on the printed report.


  • Bland M (2000) An introduction to medical statistics, 3rd ed. Oxford: Oxford University Press.