Hi everyone.
I'm analyzing the walking speed differences at two specific speeds in a sample of females and males.
Firstly I'm analyzing the differences between the two specific speeds with paired t-test.
Now I ask you for some help to understand that issue better:
I want to observe the differences by sex for each specific speed.
So I have to run single t-tests (es: slow speed males vs high speed males, and so on for females); do I have to correct all the t-tests with Bonferroni? If yes, how should I do it with R? I've found only this method:
p.adjust(try, method ="bonferroni")
where try is a vector of all p-values for a specific variable).
I am struggling to figure it out.
Hello Federico,
What's your research question(s)?
While the overall design is likely best handled as a one-between (sex), one-within (assigned speed) anova (or the equivalent regression model), it appears to me that you would have a maximum of 6 t-tests of (possible) interest:
1. Do males differ from females:
(a) combined across speeds;
(b) at slow assigned speed only ;
(c) at faster assigned speed only.
(That's up to three tests, using independent t-tests)
2. Does assigned speed matter:
(a) combined, across sex (e.g., slow vs. fast assigned paces for all participants);
(b) for males only;
(c) for females only
(That's up to three tests, using dependent t or simple repeated measures).
The R function, p.adjust, can indeed adjust individual p-values for whatever vector length (number) of test outcomes you wish. Further, it allows for adjustments other than the Bonferroni.
Good luck with your work.
go to this link on my website, deborahhilton - Favourite Links (google.com) https://sites.google.com/site/deborahhilton/favouritelinks go to the Statistics.com - statistical glossary then there is a paragraph on the Bonferroni Otherwise I have the statistical book by Armitage and Berry, Statistical methods in Medical Research, but the binding has disintegrated, and all the pages are falling out. I also find it difficult to understand as I've looked up other terminology before however if you have this in your library or you want me to find my falling apart copy let me know I can do this, I know where it is good luck this, I hope this helps
اذا كانت حجم العينة الماخوذة 30 او ااكثر نستخدام معادلة t-teast اما اذا كانت حجم العينة اقل نستخدام مان وتني @
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