NAN in post-hoc test

Comments

• Mcube78

  March 2019

  sorry, I now saw a similar post. I ran my analysis on 0.9.1, so I'll try it on 0.9.2 and re-post if needed (sorry!) :-)
• Mcube78

  March 2019

  Dear All,

  still got the NaNs above in 0.9.2. Any advice?

  Cheers

  Martin
• EJ

  March 2019

  Hi Martin,

  I'll ask the expert in our team. We are nearing a new version, so it would be great to see this fixed (if it is a bug).

  Cheers,

  E.J.
• JohnnyB

  March 2019

  Hi Martin,

  Due to the Scheffe and Tukey corrections not being suitable for RM factors, we have decided to not display those and clarify this with a footnote in the table. However, I will change the way it is being displayed, since NaN is ususally an indicator that something went wrong in the analysis.

  For now, I would advise you to use another p-value correction, such as Bonferroni or Holm.

  Kind regards,

  Johnny
• HMSTAT

  April 2019

  Hi All. I've encountered similar issue of NAN when running Games-Howell post-hoc on a one-way ANOVA using JASP 0.9.2. However, in my case this only seems to be associated with some values and with this particular post-hoc. All data has the same number of repetitions (only 2 data points for each group). As can be seen below, some pairwise comparisons come back with NAN while others are returning a value. Both Dunn and Tukey give values for all comparisons.

  

  
  
• JohnnyB

  April 2019

  Hi HMSTAT,

  To calculate the p-value, JASP uses the ptukey function from R (see also here: https://rpubs.com/aaronsc32/games-howell-test).

  It seems that for most groups, the df is very low due to only 2 observations per group, which breaks the ptukey function. If you want, you can send me your data set and I will look into this a little bit more (you can send it to j.b.vandoorn at uva.nl), but I think your n per group is simply to low.

  Kind regards,

  Johnny