πŸ—‚οΈ Categorical Data

Chi-Square Test

Test whether observed frequency distributions fit expected patterns, or whether two categorical variables are independent. Reports χ², p-value, and CramΓ©r's V effect size.

Input
Results
χ² = Ξ£ [(Oα΅’ βˆ’ Eα΅’)Β² / Eα΅’]

Degrees of freedom:

df = k βˆ’ 1 (k = number of categories)
Contingency Table

Enter observed counts in each cell. Each row represents one level of Variable 1; each column a level of Variable 2.

Results
E(i,j) = (row_i total Γ— col_j total) / grand total χ² = Ξ£ [(O βˆ’ E)Β² / E] df = (rows βˆ’ 1) Γ— (cols βˆ’ 1)

CramΓ©r's V (effect size):

V = √[ χ² / (N Γ— min(rowsβˆ’1, colsβˆ’1)) ]