Computing t for Independent Samples (pooled variance)


Variables to Enter Input Column
Variance for Group 1
Variance for Group 2
Mean for Group 1
Mean for Group 2
Number of participants for Group 1
Number of participants for Group 2
Variables below list elements of the t test computations
Values below are computed for you.
Pooled Variance S2pooled=
Standard Error of Mean 1 S2M1=
Standard Error of Mean 2 S2M2=

To test the concept: “are the two means significanctly different ?” ; which is a test of the null hypothesis that Ho: mean1 = mean2, we simply compare the “t score” observed in the table above against the “t score ” critical , which we take from a “t table ” based on the degrees of freedom of dftotal= (n1 - 1) + (n2 - 1) for the two independent sample test, at a probability level of p<0.05 is available in any t distribution table. If the “t score” observed is greater than the “t score ” critical then we reject the null hypothesis and state that the sample mean is significantly different than the population mean.

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For more information, please contact:

Professor William J. Montelpare, Ph.D.,
Margaret and Wallace McCain Chair in Human Development and Health,
Department of Applied Human Sciences, Faculty of Science,
Health Sciences Building, University of Prince Edward Island,
550 Charlottetown, PE, Canada, C1A 4P3
(o) 902 620 5186

Visiting Professor, School of Healthcare, University of Leeds,
Leeds, UK, LS2 9JT
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