Hi there, congratulations for your work inthese series of videos, there really helptful! I have a dataset with plant sprouts elongation measured in three time points. The plants have undergone different treatments (A and B, 8 replicates each). I cannot assume my data is normally distributed.. Is there a way to use Friedman's test in a equivalent mode to a Mixed Anova in R? (which was my initial thought using Treatment as a "between" subject factor and "Time" as "within" subject factor).
Hi there, you should probably look into a non-parametric ANOVA approach that also works with mixed settings, meaning between- and within-subject effects. I have used ARTool in R, which is applying rank transformation to your data and will work perfectly fine. I however have not yet had time to record videos for that. This will be a bit further down the line, unfortunately. Best Regards, Björn.
Hi! Thank you for this video. I was wondering if you could give me advice on how I should report my results. My research looks at Likert-Scale responses (ordinal values 1-5) on the perceived effect of 4 different compositions (/treatment group) of music. How can I find out which composition of music had the "biggest" perceived effect? I tried comparing median ranks to post-hoc results, however, many pairs did not demonstrate statistical significance though they had big difference in median ranks. Not sure if my question is clear but your advice would be very much appreciated!
Hi Lina, it sounds like when adjusting the p-values to be protected from Alpha error inflation, you cannot observe low enough p-values. I would supsect a small sample size (what is your N?) and effects that are not large enough to be able to observe them with your sample. The "biggest" effect would be the largest effect size for pariwise comparisons with low enough p-values, if you can observe two or more. Does that help? Cheers, Björn.
Hi, i don't have the friedman_test function of the rstatix package.. I only get the function friedmantest of the coin package but this one it not the same since it gives an error. Do you know why this is or could you help?
Hi there, do you have the latest version of the rstatix package installed? I'm running version 0.7.2 and have the friedman_test()-function. In case rstatix cannot be updated, you have to update your R version. I'm currently running 4.2.3 with rstatix 0.72. Best Regards, Björn.
@@statorials Hi! Since your video's are so good i was wondering if you could help me with another problem. Do you know a non parametric version of repeated measures ANCOVA?
You can try the art()-function of the ARTool package to achieve Aligned Rank Transformation. I have done calculations using art() for mixed approaches and put it on my list for a future video. That list is long though and I don't know yet when I can slide that it. ;-) Best Regards, Björn.
Hi there, congratulations for your work inthese series of videos, there really helptful! I have a dataset with plant sprouts elongation measured in three time points. The plants have undergone different treatments (A and B, 8 replicates each). I cannot assume my data is normally distributed..
Is there a way to use Friedman's test in a equivalent mode to a Mixed Anova in R? (which was my initial thought using Treatment as a "between" subject factor and "Time" as "within" subject factor).
Hi there, you should probably look into a non-parametric ANOVA approach that also works with mixed settings, meaning between- and within-subject effects.
I have used ARTool in R, which is applying rank transformation to your data and will work perfectly fine. I however have not yet had time to record videos for that. This will be a bit further down the line, unfortunately.
Best Regards, Björn.
Hi! Thank you for this video. I was wondering if you could give me advice on how I should report my results. My research looks at Likert-Scale responses (ordinal values 1-5) on the perceived effect of 4 different compositions (/treatment group) of music. How can I find out which composition of music had the "biggest" perceived effect? I tried comparing median ranks to post-hoc results, however, many pairs did not demonstrate statistical significance though they had big difference in median ranks. Not sure if my question is clear but your advice would be very much appreciated!
Hi Lina, it sounds like when adjusting the p-values to be protected from Alpha error inflation, you cannot observe low enough p-values. I would supsect a small sample size (what is your N?) and effects that are not large enough to be able to observe them with your sample. The "biggest" effect would be the largest effect size for pariwise comparisons with low enough p-values, if you can observe two or more.
Does that help?
Cheers, Björn.
what is ID?
Simply an identifier or case number.
Hi, i don't have the friedman_test function of the rstatix package.. I only get the function friedmantest of the coin package but this one it not the same since it gives an error. Do you know why this is or could you help?
Hi there, do you have the latest version of the rstatix package installed? I'm running version 0.7.2 and have the friedman_test()-function.
In case rstatix cannot be updated, you have to update your R version. I'm currently running 4.2.3 with rstatix 0.72.
Best Regards, Björn.
thank you! you are correct. I had an older version of R.@@statorials
@@statorials Hi! Since your video's are so good i was wondering if you could help me with another problem. Do you know a non parametric version of repeated measures ANCOVA?
You can try the art()-function of the ARTool package to achieve Aligned Rank Transformation. I have done calculations using art() for mixed approaches and put it on my list for a future video. That list is long though and I don't know yet when I can slide that it. ;-)
Best Regards, Björn.