================================================================== The gateway between this list and the sci.stat.edu newsgroup will be disabled on June 9. This list will be discontinued on June 21. Subscribe to the new list EDSTAT-L at Penn State using the web interface at http://lists.psu.edu/archives/edstat-l.html. ================================================================== . Suppose there is one factor with two levels. I could either run one-way ANOVA or unpaired t test. I always thought that the unpaired t-test would be the same as one-way ANOVA in the following sense: the F test in ANOVA for two factor level means being equal (or factor effect) would be equivalent to the unpaired t test for the difference betwen the two factor level means since F = t^2 holds in this case.
After I took a close look of the formulas, I now realize that unpaired t test is exactly equivalent to a one-way ANOVA when the latter is used to test for a difference in means between two factor levels. Then I have problem understanding the subtle difference: It seems that it is possible to have significant factor effect while there is no significant difference between the two factor level means. My question is: How is this possible? Thanks, Gang Chen
