Besides their known long-term effects, do cigarettes also cause short-term illnesses such as colds? To help answer this question, a sample of smokers was drawn. Each person was asked to report the average number of cigarettes smoked per day and the number of days absent from work due to colds last year.

a. Determine the regression line.

b. What do the coefficients tell you about the relationship between smoking cigarettes and sick days because of colds?