From 9b77e5048c1363eb2c116ebf0ee2192dcd3b92c3 Mon Sep 17 00:00:00 2001 From: zleyyij Date: Tue, 13 Feb 2024 15:18:37 -0700 Subject: [PATCH] vault backup: 2024-02-13 15:18:37 --- education/statistics/Hypothesis Tests.md | 2 ++ 1 file changed, 2 insertions(+) diff --git a/education/statistics/Hypothesis Tests.md b/education/statistics/Hypothesis Tests.md index ac6995b..5ea00f8 100644 --- a/education/statistics/Hypothesis Tests.md +++ b/education/statistics/Hypothesis Tests.md @@ -70,6 +70,8 @@ Reliable investigators test their conclusions on an independent batch of data ## Goodness of fit tests ($\chi ^2$) This test is used when you have one qualitative variable with many categories, eg the (color, size, shape) of an (item). +$$ \chi ^2 = sum(\frac{(obs_{freq} - exp_{freq})^2}{exp_{freq}}) $$ + The $\chi^2$ curve does not follow the normal curve. It has a long right hand tail. As the degrees of freedom go up, the curves flatten out, and the hump moves out to the right. $$ df = num_{terms} - 1 $$