Posted on Categories Practical Data Science, Statistics, Statistics To English Translation, TutorialsTags , , , 2 Comments on Cohen’s D for Experimental Planning

Cohen’s D for Experimental Planning

In this note, we discuss the use of Cohen’s D for planning difference-of-mean experiments.

Estimating sample size

Let’s imagine you are testing a new weight loss program and comparing it so some existing weight loss regimen. You want to run an experiment to determine if the new program is more effective than the old one. You’ll put a control group on the old plan, and a treatment group on the new plan, and after three months, you’ll measure how much weight the subjects lost, and see which plan does better on average.

The question is: how many subjects do you need to run a good experiment? Continue reading Cohen’s D for Experimental Planning

Posted on Categories Opinion, Statistics, TutorialsTags , , , 1 Comment on Remember: p-values Are Not Effect Sizes

Remember: p-values Are Not Effect Sizes

Authors: John Mount and Nina Zumel.

The p-value is a valid frequentist statistical concept that is much abused and mis-used in practice. In this article I would like to call out a few features of p-values that can cause problems in evaluating summaries.

Keep in mind: p-values are useful and routinely taught correctly in statistics, but very often mis-remembered or abused in practice.

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From Hamilton’s Lectures on metaphysics and logic (1871).
Internet Archive Book Images

Continue reading Remember: p-values Are Not Effect Sizes