1. Since b=0.8(10000/5)=1600 then a=60000-1600*20=28000. Hence the regression 
   equation is:
                income=1600(yrs_of_tenure) + 28000

2. For unit increase in yrs_of_tenure we can expect income to increase by
   $1600. The intercept indicates that a tenured faculty member with zero
   yrs_of_tenure can expect, on average, to earn $28,000.
   If the data collected includes faculty with zero yrs_of_tenure then the
   interprettation of the intercept is meaningful.

3. r=0.8 which indicates a positive linear association between income and
   yrs_of_tenure. Also, 64% of the variation in income is explained by the 
   model.