Investigators studied the relationship between screen time (measured in hours/week) and body- mass-index, BMI= wt/ht" (wt = weight in kg and ht = height in meters), in men age 25 - 45. They surveyed 6234 U. S. men in this age group, the scatter diagram for the data was homoscedastic and the BMI data was approximately normally distributed both unconditionally and in each vertical strip.

The investigators generated the following summary statistics:
X = 35 SDX = 12
Y = 27 SDy = 6 r = 0.8
where X = hours of screen-time per week, and Y = BMI.

(a) (2 pts) Find the regression equation for predicting BMI from hours of screen time.
(b) (2 pts) According to this regression, by how much does BMI increase on average for each additional hour of weekly screen time?