JohnnyB

Comments

• Hi Charles, Yes, the robust MAD is ran with the constant set to the default option of the MAD function. For the regular MAD, we run the same function but specify the constant to be equal to 1. Cheers, Johnny

  in MAD and MAD robust Comment by JohnnyB October 31
• Hi Lior, This is an excerpt from our Bayesian guidelines article (https://psyarxiv.com/yqxfr), where we discuss the error percentage for ANOVA: "For some analyses, the results are based on a numerical algorithm, such as Markov chain Monte Carlo…

  in interpreting error percentage Comment by JohnnyB September 30
• Hi Edwin, Could you specify whether you used the Bayesian ANOVA or the frequentist ANOVA? Then we can narrow down the search to where this issue might be coming from! Kind regards, Johnny

  in Why are JASP files so big? Comment by JohnnyB September 16
• Hi Cames, For the nonparametric ANOVA, when specifying a grouping factor, it needs to be at least an incomplete balanced design in order to run the Friedman or Durbin test. Such a design has the following properties (see https://en.wikipedia.org/wik…

  in Discrepancy between Bayesian and Frequentist Repeated Measures ANOVA Comment by JohnnyB August 22
• Hi rhlamber, From a quick look at the tables you included in your document, it seems that SPSS is performing fewer post hoc comparisons - it does not compare the different levels of group (sedentary vs exercised), whereas JASP does. This means that …

  in Wrong results from ANOVA post hoc Comment by JohnnyB August 15
• Hi Cesar, The Maxwell reference is central here and can be found at: https://journals.sagepub.com/doi/abs/10.3102/10769986005003269 And the Andy Field reference is his statistics text book "Discovering Statistics using SPSS". If these are …

  in Post-hoc analysis with Scheffe analysis in multiple comparisons Comment by JohnnyB July 22
• Hi gvleioras, What sort of effect sizes would you like to see? I assume that these are a bit more straightforward to implement than power analysis (which is a bigger project we will probably tackle more generally in the future). Cheers, Johnny

  in MANOVA: Effect size and power Comment by JohnnyB July 8
• Hi Herve, Dunn's post hoc test is still in the ANOVA - see the checkbox under "Post hoc tests" Cheers Johnny

  in Dunn's post hoc test Comment by JohnnyB July 8
• Hi Ajestudillo, The BF10/BF01 compares all models to the best performing model (this is a setting you can change to "compare to null model"). This means that the best performing model is at the top of your table - in this case the model wi…

  in Problems understanding Bayesian repeated measures anova Comment by JohnnyB June 27
• Hi Shem, I think this is possible to do with the "compute columns" functionality. There is an informative blogpost here: https://jasp-stats.org/2018/12/18/how-to-compute-columns-in-jasp/ This will probably not correct your p-values for mul…

  in Bayesian contrasts Comment by JohnnyB June 27
• Hi Mark, Yes, the R-code and research are there. I am currently waiting for a rewrite of the analysis, but after that is done, I will implement the analysis! For now there is R-code available at https://osf.io/gny35/ and the paper is available at ht…

  in Bayes & Wilcoxon Comment by JohnnyB June 27
• Hi RBJ, You can try tweaking the number of samples used for MCMC. This option is under the 'advanced' menu. I would suggest using the default setting when you actually want to report your results though, as decreasing the number of samples typically…

  in Bayesian Repeated Measures ANOVA with Many Models Comment by JohnnyB June 27
• Hi Elise, The R-code can be found on the OSF page of the corresponding article (under review atm). https://osf.io/ctv8a/ You give it the observations from the two groups (first two arguments of the function), then take the vector of 'deltaSamples' …

  in Bayes Factors for non-parametric tests Comment by JohnnyB June 20
• Hi Majan, What JASP reports for the Mann-Whitney test is the W statistic which is calculated by summing the ranks for one of the groups. In other words, when pooling the observations from both groups, and then assigning ranks, the W statistic is the…

  in Wrong wording in t-test Comment by JohnnyB June 17
• Hi Vicente, The Durbin test is only suitable for balanced designs (see Wikipedia https://en.wikipedia.org/wiki/Durbin_test ). I am not entirely sure why this is, but I can sort this out next week if needed. As for the the post-hoc tests, the between…

  in Durbin Test - non-parametric mixed ANOVA Comment by JohnnyB May 26
• Hi HMSTAT, The p is the p-value for the chi square statistic, whereas the pF is the p-value for the F statistic in the table. Cheers, Johnny

  in Durbin Test - non-parametric mixed ANOVA Comment by JohnnyB April 30
• Hi Darren, Apologies for the delay in answering. The Bayesian implementation is based on the test statistic (tau) and it's asymptotic distribution. In the article we only speak about the version without ties. However, even with ties present, this me…

  in Kendall Tau - Bayesian/frequentist Comment by JohnnyB April 30
• Hi Dendrite, There will be posthoc tests for interactions in the next JASP release (0.9.3) which will be released in a couple of weeks. The release after that one will have contrasts for interactions. For now, in 0.9.2, contrasts and posthoc tests …

  in Contrasts & Post-hoc in case of interaction in reapeated measure ANOVAs or factorial ANOVAs Comment by JohnnyB April 15
• 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…

  in NAN in post-hoc test Comment by JohnnyB April 13
• Hi Dendrite, Yes, this is a known issue and we are working on it - it should be fixed in the next release (0.9.3) Cheers, Johnny

  in Descriptive plots in the Repeated Measures ANOVA section Comment by JohnnyB April 11
• Hi Gabriel, We use the approach I outlined in my previous post - you can read more about it here. I am not sure what JAMOVI uses - maybe you can contact them on their github page. One thing that could cause a discrepancy is that different types of…

  in similar eta-square and partial eta-square Comment by JohnnyB April 8
• Hi Aaron, A gif to illustrate this procedure can be found here: https://jasp-stats.org/wp-content/uploads/2018/02/assumptionchecks_rep_meas.gif An overview of our tutorials (blog posts, gifs, youtube videos) can be found here: https://jasp-stats.org…

  in RM ANOVA question Comment by JohnnyB April 8
• Hi mdlee, There are two ways to go about this: In the RM ANOVA menu, you can click on the tab "additional options" and tick the box labeled "Descriptive statistics" - this will give you a table with the means for each cell of eac…

  in JASP: Means in post hoc analysis Comment by JohnnyB March 28
• Hi Pedro, To follow up on my tweet, here is an excerpt of an article we are currently working on (about the Bayesian version of the various nonparametric t-tests, found here https://arxiv.org/abs/1712.06941): "An often used standardized effect …

  in Effect size for Wilconxon signed-rank test Comment by JohnnyB March 28
• Hi Peterose1, If you want to conduct the two-sample test, this is readily available in JASP. I am still in the process of implementing the one-sample versions - if you want I can link you some R-code that gives you a Bayes factor and posterior distr…

  in Bayes Factors for non-parametric tests Comment by JohnnyB March 28
• Hi mrvallejo, The normality assumption of the ANOVA concerns the distribution of the residuals, not the raw data itself. Because the residuals are the differences between the observed dependent variable and the predicted dependent variable, we can s…

  in Testing for normality for each groups in the ANOVA Comment by JohnnyB March 25
• 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…

  in NAN in post-hoc test Comment by JohnnyB March 15
• Hi Mat, I just ran the analysis in R to check those results. Here is the code I wrote: myDat <- read.csv("/home/johnny/Downloads/airport.csv")# Take subset for "Near" conditionmyDat <- subset(myDat, LOCATION == 1)# Turn da…

  in Divergence between JASP and SPSS ouptuts when computing polynomial contrasts for within-sjts designs Comment by JohnnyB February 21
• Hi Mark, Thanks for sharing this. The underlying algorithm introduces some degree of variation (there is Gibbs sampling both for dealing with rank data and for sampling from the delta posterior distribution). I have just implemented some more stabi…

  in Bayesian t-test - same data different BF10 each time Comment by JohnnyB February 6
• In addition I looked into this discrepancy a bit more, and there just seem to be multiple ways of computing the confidence intervals for cohen's d (differing in their approximations). There's an interesting post and simulation study here. Basically…

  in What denominator does the Cohen's d use on JASP?? Comment by JohnnyB January 31
More Comments