Wednesday, May 28, 2014

2-Sample Unpooled t-Test Excel Calculations, Formulas, and Tools

This is one of the following six articles on 2-Independent-Sample Unpooled t-Tests in Excel

2-Independent-Sample Unpooled t-Test in 4 Steps in Excel 2010 and Excel 2013

Variance Tests: Levene’s Test, Brown-Forsythe Test, and F-Test in Excel For 2-Sample Unpooled t-Test

Excel Normality Tests Kolmogorov-Smirnov, Anderson-Darling, and Shapiro-Wilk For 2-Sample Unpooled t-Test

2-Sample Unpooled t-Test Excel Calculations, Formulas, and Tools

Effect Size for a 2-Independent-Sample Unpooled t-Test in Excel 2010 and Excel 2013

Test Power of a 2-Independent Sample Unpooled t-Test With G-Power Utility

 

2-Sample Unpooled t-Test

Excel Calculations,

Formulas, and Tools

 

Excel Data Analysis Tool Shortcut

This two-independent-sample, unpooled t-Test can be solved much quicker using the following Excel data analysis tool:

t-Test: Assuming Unequal Variances

This Excel tool is part of the Data Analysis Toolpak that is an add-in which ships with Excel but must first be activated by the user before it is available.

Before this test is employed, all required assumptions such as normality of data must be verified as was done.

As mentioned, the data should be input with the sample having the largest mean being designated as the sample group. Doing so ensures that the Excel output will have the same signs for the t Value and Critical t Value. If the sample with the smallest mean is input is the first sample, the t Value will correctly be negative but the Critical t Value will be incorrectly listed by Excel as being positive.

This tool will be applied to the following data set using the same data as the preceding example in this section:

t-test, t test, statistics, excel, excel 2010, excel 2013,unpooled t test,unpooled t-test
(Click On Image To See a Larger Version)

The completed dialogue box for this tool is shown as follows:

t-test, t test, statistics, excel, excel 2010, excel 2013,unpooled t test,unpooled t-test (Click On Image To See a Larger Version)

Clicking OK will produce the following result. This result agrees with the calculations that were performed in this section.

t-test, t test, statistics, excel, excel 2010, excel 2013,unpooled t test,unpooled t-test (Click On Image To See a Larger Version)

The calculations to create the preceding output were performed as follows. The individual outputs are color-coded so it is straight-forward to match the calculations with the outputs of the tool.

t-test, t test, statistics, excel, excel 2010, excel 2013,unpooled t test,unpooled t-test (Click On Image To See a Larger Version)

t-test, t test, statistics, excel, excel 2010, excel 2013,unpooled t test,unpooled t-test (Click On Image To See a Larger Version)

t-test, t test, statistics, excel, excel 2010, excel 2013,unpooled t test,unpooled t-test (Click On Image To See a Larger Version)

 

Excel Statistical Function Shortcut

The stand-alone Excel formula to perform a two-independent sample, unpooled t-Test is shown as follows. If the resulting p Value is smaller than α for a one-tailed test or α/2 for a two-tailed test, the difference between the means of the samples is deemed to be statistically significant. This indicates that the two samples were likely drawn from different populations.

t-test, t test, statistics, excel, excel 2010, excel 2013,unpooled t test,unpooled t-test(Click On Image To See a Larger Version)

 

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Statistical Topics and Articles In Each Topic

 

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