Timeline for Differences in p-values between general linear model, t-test and non-parametric test
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 15, 2017 at 9:13 | comment | added | Fernandez | Main question was about understanding why my approximation was a bad one. And you helped a lot. Even from mobile. ;) Sometimes some of the most basic principles get entangled in my head and I need a helping hand just to see clearly where I am standing and why. Thank you again. I am now facing other problems related to non-parametric methods and small sample sizes, but that might be another question. | |
| Jun 15, 2017 at 8:26 | comment | added | Michael M | Good points. In your specific setting, switching to a paired (within-subject) strategy will help a lot. But I am aware that your question was about pairwise t-tests versus t-tests on parameters of linear models. | |
| Jun 15, 2017 at 6:42 | vote | accept | Fernandez | ||
| Jun 15, 2017 at 6:42 | comment | added | Fernandez | About multiple testing. I deliberately omitted the subject from the question in order not to complicate it more. I understand that if we are making the two comparisons on this dataset, the resulting p-values must be corrected using a proper technique. But the problem is similar to the one that originated the question, especially if the correction makes the comparison go against the main researcher intuition. What I usually do is to provide the researcher with both the unadjusted and adjusted p-values, so they can see how the evaluation of multiple hypotheses affects their results. | |
| Jun 15, 2017 at 6:38 | comment | added | Fernandez | First of all, let me thank you for your helpful and informative answer. I understand the reasons for not using the linear model. I have to confess that I generally do not pay enough attention to the general assumptions that every test must fulfill, maybe carried away and influenced by the general tendency to use more familiar techniques or the lack of proper statistical advice. I think I am going to continue my analysis with non-parametric tests, due to the small sample size and differences in variability. | |
| Jun 14, 2017 at 14:26 | history | answered | Michael M | CC BY-SA 3.0 |