posted by kristen .
In a study that was highly published doctors discovered that aspirin helps prevent heart attacks. The research project which was scheduled to last 5 years employed 22,000 american physicians (all male). Half took an aspirin tablet 3 times a week while the other half took a placebo on the same schedule. After 3 years researchers determined that 104 of those who took aspirin and 189 of those who took placebo had heart attacks. Do the results indicate that aspirin is effective in reducing the incidence of heart attacks? Provide the test statistic and the critical value.