1. Case control study examined 134 cancer patients and 134 matched cancer-free controls. Each patient was matched to exactly 1 control , resulting in 134 pairs. 13 pairs had positive smoking history for both the case and the control and for 25 pairs the case had a positive smoking history and control had a negative smoking history

Control

Case + 13(+),25(-), total=38

Case - 4 (+), 92 (-)= 96

Total 17 (+) 117 (-)= 134

a) for what proportion of the patient pairs does the case smoking history match the control smoking history?

b) For what proportion of the patient pairs does the case smoking history differ from the control smoking history?

c) calculate the value of the McNemar test statistic. Report the test statistic and its degrees of freedom.

d) last question. If the McNemar test rejects the null hypothesis at 0.05 sig level. What happens, you reject the null? and conclude what?