Cotinine is a metabolite of nicotine. Investigators wish to study the relationship between cotinine and number of cigarettes per day in smokers. Data were collected among 15 smokers, and the regression analysis results are presented below.

Consider the linear relationship between x=Number of Cigarettes per Day as the independent variable and y=Serum Cotinine (ng/mL) as the dependent variable.

ANOVA SS MS F Significance F 7.93873 Regression 65615.51 65615.51 3 0.014532 Rosidual 13 107448.1 8265.237 Total 14 173063.6 Coofficiant Upper Standard Error ! Stat P.value Lower 95% 95% 0.24131 Intercept 56.87401 46.32486 1.227721 -43.2048 156.9528 0.01453 X Variable 1 9.645085 3.423186 2.817576 2 2 249742 17.04043