1. Using StatCrunch, calculate the chi-square statistic and degrees of freedom for the following set of data for 300 people:

Group A Group B Group C Total

Had flu shot 20 30 32 82

Didn’t have flu shot 80 70 68 218

Total 100 100 100 300

Is the value of the chi-square statistically significant at the 0.05 level?

3. Using StatCrunch, calculate the chi-square statistic and degrees of freedom for the following set of data for 180 people undergoing a knee replacement treatment with a drug supplement:

Treatment with drug X Treatment without Drug X Total

Had > 8 wk rehab 18 32 50

Had < 8 wk rehab 70 60 130

Total 88 92 180

Is the value of the chi-square statistically significant at the 0.05 level?

4. Write a paragraph summarizing the results of the analysis in Exercise 3.

8. The relationship between cigarette smoking and major depressive disorder has been studied for decades. In the doc sharing area of the course, you will find an excel spreadsheet of data from a study on smoking and depression by the St Louis Epidemiologic Catchment Area Survey of the National Institute of Mental Health. The file is labeled “Catchment Area Survey”. Using this data setin StatCrunch, calculate the chi-square statistic and degrees of freedom for the items “smoker” and a measure of depression, “FeltDown”. Construct a contingency table for this data as we did in week 1. Be sure to include and label the row, column and total %’s as well as the expected counts. Is the value of the chi-square statistically significant at the 0.05 level? Any reason to use a correction to the chi-square test here given your expected counts?

9. Write a paragraph summarizing the results of the analysis in Exercise 8. What can you conclude about smoking and depression (“Feeling Down”) in this sample?

10. Below are three (a-c) sets of cells of 2 X 2contingency tables including the expected frequencies (Totals not included). Identify which statistical procedure would be appropriate for each, using the most conservative approach.

a.

b.

c.