Swor et al. (A-11) examined the effectiveness of cardiopulmonary resuscitation (CPR) training in people over 55 years of age. They compared the skill retention rates of subjects in this age group who completed a course in traditional CPR instruction with those who received chest-compression–only cardiopulmonary resuscitation (CC-CPR). Independent groups were tested 3 months after training.

Among the 27 subjects receiving traditional CPR, 12 were rated as competent. In the CC-CPR group, 15 out of 29 were rated competent. Do these data provide sufficient evidence for us to conclude that the two populations are not homogeneous with respect to competency rating 3 months after training?

Let a ¼ .05.