t-Test

Paired Two Samples

Performs a paired two-sample student's t-test to determine whether a sample's means are distinct. This t-test form does not assume that the variances of both populations are equal. Use this paired test when there is a natural pairing of observations in the samples, such as when a sample group is tested twice - before and after an experiment.

Example

A paired feeding experiment was conducted with pigs on the relative value of limestone and bonemeal for bone development. The results are given in the following table

Test the significance of the difference between the means.

Analyzing the data

For analysing the above data , first enter the data in a separate worksheet of the same workbook and enter the data as did in the earlier exercise.

• On the main menu Click Tools option
• Click Data Analysis option from the displayed window

• From the displayed Analysis Tool Pack window, Click t-Test :Paired Two Samples for Means to get the following screen

• Enter the cell reference, that is B1 : B11, As Variable 1 Range for the first range of data to be analyze. The range must consist of a single column or row. And similarly enter the Variable 2 Range is C1:C11 .

• Hypothesized Mean Difference : Enter value of 0 (zero) indicates that the sample means are hypothesized to be equal.

• Click on the Labels check box to consider the column label as the variable names.

• Alpha : Enter the confidence level for the test. This value must be in the range 0...1.

• Output Range : Enter the reference Cell as A13 to keep the results on the worksheet. The out will be displayed as shown below