Independence and Homogeneity¶

Test for Independence¶

Contingency table: 2-way table

Conditions for Independence Test¶

• Random sample
• Independent values
  • Sample with replacement
  • or $n < 0.1N$
• Large counts condition
  • Expected values $\geq 5$
  • or $\geq 80\%$ of expected values $> 5$ and all are $\geq 1$

Calculate Independence Test¶

• $Expected\ value$ = $Probability\ in\ row \times Probability\ in\ column \times Total\ number\ in\ the\ sample$ = $\dfrac{Row\ total \times Column\ total}{Total\ number\ in\ the\ sample}$
• $dof = (N_{row} -1)(N_{col} -1)$