Post-hoc planned and unplanned comparisons
Posted: Thu Dec 02, 2021 9:12 am
I am running a two-way repeated measures ANOVA (exercise intensity x time), in which I have 3 intensities and 5 time points.
I have a signifcant intensity x time interaction, and so ran the post-hoc using Tukey corrections.
However, for the corrections, there are many comparisons which I not interested in. For example, let's say the intesities are 100, 80 and 60% of peak power output, and the time-points are baseline, 25, 50, 75 and 100% task completion. I am only interested in whether within each intensity, there is a change over time relative to baseline (e.g. does my dependent variable change over time for the 100% peak power output trial), and whether at a specific time points (e.g. 50% task completion), there is a difference between the 3 intensities.
Yet, the post-hoc corrects for a number of unplanned comparisons (e.g. it will compare 25% task completion at 100% peak power output vs. 75% task completion from 80% peak power output).
Is there any way that I can specify only the planned comparisons which I am interested in, so that the p value is not adjusted for all these unplanned comparisons?
I have a signifcant intensity x time interaction, and so ran the post-hoc using Tukey corrections.
However, for the corrections, there are many comparisons which I not interested in. For example, let's say the intesities are 100, 80 and 60% of peak power output, and the time-points are baseline, 25, 50, 75 and 100% task completion. I am only interested in whether within each intensity, there is a change over time relative to baseline (e.g. does my dependent variable change over time for the 100% peak power output trial), and whether at a specific time points (e.g. 50% task completion), there is a difference between the 3 intensities.
Yet, the post-hoc corrects for a number of unplanned comparisons (e.g. it will compare 25% task completion at 100% peak power output vs. 75% task completion from 80% peak power output).
Is there any way that I can specify only the planned comparisons which I am interested in, so that the p value is not adjusted for all these unplanned comparisons?