Chi Square

Question 1

Function of Chi Square?

Answer 1

investigating relationship between 2 categorical variables
-makes inferences about likelihood –> significant chi square tells us if you’re in one specific category for first variable, how this affects likelihood to be part pf specfic category in 2nd variable

Question 2

Hypothesis testing

Answer 2

compare observed values in sample to expected -are the differences significant?
test this with the chi square test:
larger chi square value = more likely you can reject nul (=significant)

χ^2 = ∑(𝑂−𝐸)^2 divided by 𝐸

Question 3

Assumptions

Answer 3

no more than 25% cells should have expected value less than 5
no individual cell should have expected value less than 1

Question 4

Degrees of freedom

Answer 4

(no. of rows-1) x (no. of columns -1)

Question 5

What type of variables are needed?

Answer 5

Both need to be categorical

eg. gender