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Why the p-value of t.test() is not statistically significant when mean values look really different

I agree with @pikachu that the standard deviations are too large compared with the difference between means for a t test to find a significant difference. Thank you for posting your data. It is always ...
• 55.7k
Accepted

Welch test seems to perform much worse than equal variance t-test

You are using a flawed metric for the performance of the test by focusing only on the power to detect a difference, but ignoring the possibility of falsely rejecting the null hypothesis. If you just ...
• 7,239
Accepted

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• 6,486

How to calculate the PDF of the 'difference' between two Beta distributions?

I know this is a bit of an old question but for what it's worth there is an established closed-form solution to this problem, found by Pham-Gia, Turkkan, and Eng in 1993. It's a piecewise solution ...
• 241

Welch test seems to perform much worse than equal variance t-test

This is a concern about the power of the Welch Test as compared to the textbook t test. Let's set up little simulation experiment and see if there are any discrepancies. The things that we can ...
• 35.1k
Accepted

Comparison of ranked lists

Summary I share my thoughts in Details section. I think they are useful in identifying what we really want to achieve. I think that the main problem here is that you haven't defined what a rank ...
• 2,701
Accepted

Check for significant difference between numbers of sightings per cardinal direction

First off, methods such as ANOVA and Kruskal-Wallis pay no attention to the circular nature of data such as yours. It's not clear how you imagine applying either, but if you intend to regard direction ...
• 55.2k

Why the p-value of t.test() is not statistically significant when mean values look really different

When you consider the difference between means you have to use a different unit than the simple absolute difference. Take into account that you are measuring the difference in means produced by two ...
• 6,924
Accepted

MLM / HLM Equal sample sizes needed between groups?

I would not advise dropping the "extra" 50 participants. This will lead to a reduction in statistical power. While, in a perfect world, it is better to have equal sized groups (more ...
• 59.7k

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