JohnnyB

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 each factor combination…

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 size …

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" condition myDat <- subset(myDat, LOCATION == 1) # Turn data frame int…

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 sta…

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. Basicall…

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

Hi Francesco, Thanks for reporting it, it seems that eff.size package has a new version that has a slightly different algorithm from the previous one - I will update the JASP code accordingly so the next version will have the same output again! Ki…

in What denominator does the Cohen's d use on JASP?? Comment by JohnnyB January 30

Hi Peter, So JASP features multiple p-value corrections (Scheffe/Holm/etc) - these are done with the multcomp package (or sometimes with the p.adjust function). This package is used for the standard post hoc comparisons and it provides us with th…

in ANOVA's post-hoc tests algorithms Comment by JohnnyB January 23

Hi Alebyk, The difference lies in whether a normal approximation is used for the p-value. From the SciPy page: "Because the normal approximation is used for the calculations, the samples used should be large. A typical rule is to require that n >…

in Wilcoxon signed rank test - Jasp vs Python, slightly different p values Comment by JohnnyB January 11

Hi Michif, The polynomial contrasts in JASP are calculated with the "contr.poly()" function in R, the result of which is then supplied to the "contrast()" function of the emmeans package. This is also the function that gives the t value for the mod…

in Trend analysis (NHST) in JASP Comment by JohnnyB December 2018

HI Michif, I just tried to reproduce your bug in the build version of JASP, and could not reproduce it. It is probably solved in the next release of JASP, since we improved some state issues, but I will check back with you after it is released to s…

in Error messages and other issues Comment by JohnnyB June 2018

Hi, If you look at the table when you only select MW (or, if i remember correctly, look at the footnote of the joint table), it will mention which effect size metric. I think it's the rank biserial correlation. Please let me know if this already c…

in What denominator does the Cohen's d use on JASP?? Comment by JohnnyB June 2018

Hi Chris, The next release, which is right around the corner, will have both the Kruskal Wallis and Friedman tests! Cheers, Johnny

in Is JASP capable of running Kruskal Wallis test and Multivariate Analysis of Variance? Comment by JohnnyB May 2018

Hi Phil, The choice for effect sizes for the two wilcoxon tests is based on the following paper: * Kerby, D. S. (2014). The simple difference formula: an approach to teaching nonparametric correlation. journals.sagepub.com/doi/full/10.2466/1…

in McNemar and rank-biserial correlation Comment by JohnnyB March 2018

Hi Cscmac, Interestingly enough there are multiple ways of calculating cohen's d. The difference lies in how the standard deviations are pooled. In JASP we have chosen to use the same method as applied by the effsize package in R: library(effsiz…

in What denominator does the Cohen's d use on JASP?? Comment by JohnnyB March 2018

Hi VC, After an intense investigation, I am not able to pinpoint exactly what SPSS does, sadly enough. If you have any idea, then I would greatly appreciate being pointed in the right direction JASP uses the car package in R - so I'm able to rep…

in ANOVA Warning Comment by JohnnyB November 2017

Hi MMA, Please see the R-code below, it computes the standard deviation of the posterior, based on the difference between the posterior median and the upper or lower value of your credible interval: abs(posteriorMedian - lowerCI) / qnorm( (1+p…

in Informed Prior Bayesian Paired Samples t-test Comment by JohnnyB October 2017

Hi Raph, Thank you for bringing this to our attention, and my apologies for the tardy reply. After reading up on effect sizes for within subjects designs, and consulting some of the true statistics guru's at our department, I have come to the concl…

in similar eta-square and partial eta-square Comment by JohnnyB July 2017

Hi, I just looked into this, and JASP uses the shapiro.test() function in R. For the two-sample t-test, JASP does this separately for each group, so you get two Shapiro statistics and p-values. It might be the case that you calculated the aggregate…

in Different Shapiro-Wilk test results in R, JASP and SPSS? Comment by JohnnyB July 2017

Hi Philip, If I understand correctly, you have two independent variables (probability and value) with six levels each, but are they measured between or within subjects? If you have your data in the wide format, with each column containing the obser…

in Model Involving both Continuous and Categorical Variables using the ANCOVA? Comment by JohnnyB June 2017

Dear Philip, You are correct in that you can specify the Bayesian ANCOVA in these two ways. I made two jasp files for you so you can see it for yourself. It all depends on how you have your data formatted. If your data is in the wide data-format, y…

in Model Involving both Continuous and Categorical Variables using the ANCOVA? Comment by JohnnyB June 2017

Howdy, Stranger!

JohnnyB

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