d06-1-the-chi-square-test-for-independence
WATCH this Khan Academy video: Contingency table chi-square test, to gain an understanding of the chi-square test.
This week we will be discussing the chi square statistic. We use chi square when we consider relationships between categorical variables.
For instance, we might look at whether political party affiliation is related to gender of voter. Are men more likely to join one political party, and women more likely to join another political party?
For the chi square test, we classify every subject into two categories:
1) their gender,
2) their political party affiliation.
The chi square statistic looks at whether the number of subjects in each combination of both ‘gender’ and ‘political party affiliation’ (cell of the chi square table) is greater than that expected by chance alone.Must post first.
***INSTRUCTIONS***
Answer both questions in your initial response:
- What are the assumptions/requirements for performing the Chi-Square Test for Independence?
- The table below is from a study conducted with the stated objective of addressing cell phone safety by understanding why people use a particular ear when speaking on a cell phone. The goal was to determine whether the ear choice is associated with auditory or language brain hemispheric dominance. Assume that one wants to test the claim that handedness and cell phone ear preference are independent of each other. Based upon the data provided in the chart, can you perform a Chi-Square Test for Independence? Why or why not?
| Right Ear | Left Ear | No Preference | |
| Right-Handed | 410 | 170 | 37 |
| Left-Handed | 16 | 45 | 7 |