Following is a 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

Total88 92 180

a.Calculate the chi-square statistic [10 points]

b.Is the value of the chi-square statistically significant at the 0.05 level? [3 points]

c.Write a paragraph summarizing and interpreting (in plain English/non-statistical language) the results of the chi-square analysis. [7 points]

ANS.

a.

b.

c.