Question: Ten adults completed a six-week smoking cessation program. The program coordinator suspected that the number of years a person smoked before entering the program was associated with the number of days that they remained smoke-free in the year after starting the smoking cessation program. (5 points)

a. What is the independent variable? (¼ pt)

b. What is the dependent variable? (¼ pt)

c. What type of data is the dependent variable? (¼ pt)

d. What is the mean number of days the participants remained smoke-free since entering the program? (¼ pt)

e. Using simple, linear regression for this data, what is the formula of the line that best fits these data? (½ pt)

f. Is the slope of this regression line statistically significant? What does it mean when the slope is statistically significant? (½ pt)

g. How many days would you expect a 15-year smoker to remain smoke-free after the smoking cessation program? (½ pt)

h. What percentage of the variance of number of days remaining smoke-free is explained by knowing the number of years smoked before the intervention? What percentage of the variance cannot be explained? (½ pt)

i. What other factors could account for the variance that is not explained by knowing the number of years smoked? (½ pt)

j. What percentage of the variance of number of days remaining smoke-free is explained by knowing the number of years smoked before the intervention if the program only included smokers who have smoked more than the past five years? (½ pt)

k. Why are the answers to h and j different? (½ pt)

l. What is the correlation coefficient for the original data? What does it mean? (½ pt)