In the 1960s, the data in Table 8.12 were collected for 21 countries on deaths from coronary heart disease per 100,000 persons of age 35–64, and annual per capita cigarette consumption [13]. Draw a scatter diagram and estimate a regression equation to see if there is a statistical relationship between these variables.

a. Which variable did you use as the dependent variable? Explain your reasoning.

b. Is the estimated slope statistically significant at the 5 percent level?

c. Does the estimated value of the slope seem plausible?