Use the data in Exercise 19.8 to demonstrate how chi-square varies as a function of sample size.

a) Double each cell entry and recompute chi-square.

b) What does this have to say about the role of the sample size in hypothesis testing?

Exercise 19.8

We know that smoking has all sorts of ill effects on people, and among other things there is evidence that it affects fertility. Weinberg and Gladen (1986) examined the effects of smoking on the ease with which women become pregnant. They took 586 women who had planned pregnancies, and asked them how many menstrual cycles it had taken for them to become pregnant after discontinuing contraception. They also sorted the women into whether they were smokers or nonsmokers. The data follow.

Does smoking affect the ease with which women become pregnant? (I do not recommend smoking as a birth control device.)

Transcribed Image Text:

1 Cycle 2 Cycles 3+ Cycles Total Smokers 29 16 55 100 Nonsmokers 198 107 181 486 Total 227 123 236 586