In a study to estimate the effects of smoking on routine health risk, employees were classified as continuous smokers, recent ex-smokers, long-term ex-smokers, and those who never smoked. Samples of 96, 34, 86, and 206 members of these groups were taken. Sample mean numbers of mean health risk rates per month were found to be 2.15, 2.21, 1.47, and 1.69, respectively. The F ratio calculated from these data was 2.56.
a. Prepare the complete analysis of variance table.
b. Test the null hypothesis of equality of the four population mean health risk rates.