F IL E A nutritionist wants to understand the influence of income and healthy food on the incidence o f smoking. He collects 2009 data on the percentage o f smokers in each state in the U.S. and the corresponding median income and the percentage o f the population that regularly eats fruits and vegetables. A portion o f the data is shown in the accompanying table; the com plete data set can be found on the text website, labeled Smoking. _______________ State Smoke (%)

Fruits/Vegetables

(%)

Median income AK 14.6 23.3 61,604 AL 16.4 20.3 39,980 WY 15.2 23.3 52,470 SOURCE: C e n te rs fo r D is e a s e C o n tr o l a n d P re v e n tio n a n d U.S. C e n s u s B u re a u .

a. Estimate: Smoke = β + β1 Fruits/Vegetables +

β 2Median Income + ε .

b. At the 5% level o f significance, are the explanatory variables individually and jo in tly significant? Explain.

c. Use the sample correlation coefficients to evaluate the potential problem o f m ulticollinearity.