JohnnyB

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• Hi JLeborgne, In essence, the analysis is indeed running paired samples t-tests. We use the emmeans package for this in R. Are you assuming equal variances or not? Maybe that is causing the different results. JASP offers both options (equal varianc…

  in RM ANOVA - Post hoc Bonferroni comparison? Comment by JohnnyB February 2020
• Hi Elnino, What error message are you getting? The only R package you need installed is the logspline package - you can install it with install.packages("logspline"). After that all code should run. If you have any additional questions abo…

  in Bayes Factors for non-parametric tests Comment by JohnnyB February 2020
• Hi AMa, JASP uses the emmeans/lsmeans package to compute the posthoc results: We first create a reference grid and estimate the marginal means with the lsmeans function by providing the ANOVA model and which factors to use for post hoc tests. Then w…

  in ANOVA post-hoc t-value calculation Comment by JohnnyB February 2020
• Hi mcp, I think that error is not just concerning the Kruskal Wallis test, but the overall ANOVA. It seems that you only have a single observation per cell of the interaction effect, so when you include that effect, there is no way of calculating th…

  in kruskall-wallis analysis problem Comment by JohnnyB February 2020
• Hi, Apologies for the late reply, and thanks for your insightful post. You are right that we use the MBESS package for computing the confidence intervals around the effect sizes. We do this as follows: unlist(conf.limits.nct(ncp = -0.072947, 59)[c(…

  in What denominator does the Cohen's d use on JASP?? Comment by JohnnyB January 2020
• Yes! I was waiting till all the internal JAPS rewrites were done, which almost seems to be the case. Implementing the Bayesian Spearman's rho and one-sample Wilcoxon tests is at the top of my JASP todo list =)

  in Spearman's correlation Comment by JohnnyB December 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 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…

  in NAN in post-hoc test Comment by JohnnyB April 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
• 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 2019
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