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JohnnyB

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