Practice Chi-Square Test in Math
Use these practice problems to test your method after reviewing the concept explanation and worked examples.
Quick Recap
A hypothesis test that compares observed frequencies to expected frequencies using the chi-square statistic to assess independence or goodness of fit.
You expect a die to land on each face about \frac{1}{6} of the time. You roll it 600 times and compare what you observed to what you expected. If the differences are small, the die is probably fair. If they're large, something is off. The chi-square statistic measures 'how far off are the observed counts from what we expected?'
Example 1
mediumA die is rolled 60 times. Observed: 1โ8, 2โ12, 3โ9, 4โ11, 5โ13, 6โ7. Conduct a chi-square goodness-of-fit test at \alpha=0.05.
Example 2
hardA 2ร2 table: Men: 30 prefer A, 20 prefer B. Women: 15 prefer A, 35 prefer B. Test independence of gender and preference at \alpha=0.05.
Example 3
easyFor a chi-square test with observed=15, expected=20 for one category, calculate that category's contribution to the \chi^2 statistic.
Example 4
hardA survey of movie preferences across three age groups produces a 3ร4 contingency table (3 age groups, 4 movie genres). State H_0 and H_a, calculate degrees of freedom, and explain what a significant result would mean.