Timeline for Nested data analysis using nlme: Analysis leaves out factor levels
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
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| Nov 10, 2014 at 12:43 | comment | added | psarka | Take a look at testInteractions (from phia package) or glht (from multcomp package). | |
| Nov 8, 2014 at 13:54 | comment | added | user55987 | Thanks for your comments, I have a much better understanding now. I still have one question regarding the results: is there a way to get pairwise comparisons using nlme? I don't want to compare the factor levels to a baseline, but would also like to get the p-values of the comparisons between all durations. | |
| Nov 3, 2014 at 9:42 | comment | added | Roland |
The "missing" level is always the first one in levels(yourFactorVariable), i.e., the first value after alphabetical sorting per default.
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| Nov 3, 2014 at 8:12 | comment | added | psarka | I am not sure, if it is always the last factor level that is missed, but it should not make a lot of difference. As for interpretation, I really recommend page 13 of that pdf file. In your case the reasoning will be very similar. For example, the coefficient -1.94 near duration50 (in my table) means that the response is on average lower by -1.94 with duration 50 compared to duration 1000 (the missed baseline level), and the difference is significant. | |
| Nov 2, 2014 at 22:13 | comment | added | user55987 | Thanks! To clarify: I asked the very general question to check if there is a better way to deal with nested data than my approach. I am basically running three analyses (1 for each response) like the one I posted. Regarding the output: I am very sorry, but I simply missed to post the interaction results from my output. You mention that there is a baseline compared to which the two others are compared. Is this always the last factor level like in your output? How would this output be interpreted? I need to analyze which factor levels are significantly different. Is this possible? | |
| Nov 2, 2014 at 21:19 | history | answered | psarka | CC BY-SA 3.0 |