Nonparametric Friedman test - repeated measures and repeated subjects

Comments

• EJ

  December 2020

  Hi ARF,

  I do not know why you would want to subsample, but I will take this as a given. One issue is whether the subsamples are partially overlapping, as you'd get from a standard bootstrap approach. If so, this overlap needs to be taken into account, complicating matters. If you just split the original data into nonoverlapping subsets then each subset gives you a feature. For simplicity you could focus on the point-estimate and then analyze the results with a repeated measures ANOVA/linear mixed model?

  Cheers,

  E.J.
• ARF

  January 2021

  Hi E.J,

  Sorry, I missed the notification of your reply. I really appreciate you taking the time to answer my question! :)

  I am interested in subsampling because acquiring the full dataset requires 15 minutes. As so, I was testing if I select fewer data points what would be the impact on the histogram features that I want to extract on a further step by using that subset.

  I had that detail into consideration, so my subsets do not overlap.

  But should I use repeated measures ANOVA with such a small sample (total N) and unbalanced samples in each session?

  Maybe I need to add 2 within-subject factors? subset (= full; subset1; subset2) and session (= session1; session2; session3; session4, to account for repetitions of the same subject)?

  Sorry, I feel that I lack experience in applied biostatistics and that I am always violating some assumption by using parametric testing.

  Thank you!
• EJ

  January 2021

  Hello ARF,

  Well, this is somewhat of an usual situation and I'm not sure! Low N is never helpful, but you seem to have many observations per subject...you might want to plot the effects of interest per subject perhaps

  Cheers,

  E.J.
• ARF

  February 2021

  Hi EJ,

  Thanks a lot for your feedback! :)

  Cheers,

  ARF