Does auto safety education increase the use of auto safety d

Does auto safety education increase the use of auto safety devices? Researchers at the University of California at San Francisco gave 78 couples randomly selected from a group of 136 expectant couples a special 30-minute lecture on the value of child safety seats. Contacted 4 to 6 weeks after the birth of their children, the researchers found that 96% of those who had attended the lecture claimed that they were using the safety seats, as did 78% of the 58 couples who did not attend the lecture.

a) Is this difference in percentages large enough to imply that the lecture was effective in increasing the percentage of couples who say that they use child safety seats? Test using ? = .0 05 .

b) Find the p-value for the test.

Solution

a) H0: p1=p2

H1: p1>p2

z=2.23

b) p=0.0006