1. When do we use chi-square tests?

2. What are observed frequencies v expected frequencies?

3. Distinguish between the goodness of fit test and the chi-square analysis. When would you use each one?

4. Imagine a town that boasts clear skies 80% of the time. You record the weather for 78 days and get the following: Clear skies 59 days, cloudy skies 19 days.

a. Calculate the degrees of freedom for the chi-square test for goodness of fit.

b. Determine the observed and expected frequencies.

c. Calculate the differences between frequencies and calculate the chi-square statistic.

Category	Observed (O)	Expected (E)	O - E	(O - E)^2	[(O - E)^2]/E
Clear Skies
Unclear Skies