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Origin and Robustness of "Equal Variances Not Assumed" Independent Samples T-Test

Question & Answer


Question

I would like some information on the origins and limits of use of the "Equal Variances Not Assumed" test that is produced when one runs the Independent Samples T-test in SPSS Statistics. For some of my analyses, the two groups are extremely different in size.  In some of these analyses, the very small groupmay have a variance of 0, whereas the larger group does have variance. Do such extreme differences in group size and invariance invalidate the "Equal Variance Not Assumed" t-test results?

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Historical Number

40423

Document Information

Modified date:
16 April 2020

UID

swg21497421