A more complete set of data on heart attacks and aspirin, from which Table 6.10 was taken, is shown below. Here we distinguish not just between Heart Attacks and No Heart Attacks, but also between Fatal and Nonfatal attacks.

Myocardial Infarction Fatal Attack NonFatal Attack No Attack Total Placebo 18 171 10,845 11,034 Aspirin 5 99 10,933 11,037 Total 23 270 21,778 22,071

a. Calculate both Pearson’s chi-square and the likelihood ratio chi-square table. Interpret the results

b. Using only the data for the first two columns (those subjects with heart attacks), calculate both Pearson’s chi-square and the likelihood ratio chi-square and interpret your results.

c. Combine the Fatal and Nonfatal heart attack columns and compare the combined column against the No Attack column, using both Pearson’s and likelihood ratio chisquares. Interpret these results.

d. Sum the Pearson chi-squares in

(b) and

(c) and then the likelihood ratio chi-squares in

(b) and (c), and compare each of these results to the results in (a). What do they tell you about the partitioning of chi-square?

e. What do these results tell you about the relationship between aspirin and heart attacks?