Some researchers have observed a greater airway resistance in smokers than in nonsmokers. Suppose a study, conducted to compare the percent of tracheobronchial retention of particles in smokingdiscordant monozygotic twins, yielded the following results:

Percent Retention Percent Retention Smoking Twin Nonsmoking Twin Smoking Twin Nonsmoking Twin 60.6 47.5 57.2 54.3 12.0 13.3 62.7 13.9 56.0 33.0 28.7 8.9 75.2 55.2 66.0 46.1 12.5 21.9 25.2 29.8 29.7 27.9 40.1 36.2 Do these data support the hypothesis that tracheobronchial clearance is slower in smokers? Let a ¼ :05. Determine the p value for this test.