The results of current study regarding smoking and three kinds of illness are shown in following table.
Illness Non-Smokers Smokers Totals
Emphysema 20 60 80
Heart problem 70 80 150
Cancer 30 40 70
Totals 120 180 300
We are interested in determining whether or not illness is independent of smoking.
a. Describe the null and alternative hypotheses to be tested.
b. Show the contingency table of expected frequencies.
c. Calculate the test statistic.
d. The null hypothesis is to be tested at 95% confidence. Find out the critical value for this test. What do you conclude?
e. Find out the p-value and perform the test.