Test for one mean

Command:

Tests Test for one mean

Description

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:

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.

Results

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

Literature

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