The equation of the regression line for the data in the table is ý = 4.1x - 139,
where x represents the height and ŷ is the predicted walking speed.

what is the meaning of 4.1 in the equation?
a. for every 1 m/min increase in walking speed, height increases by
4.1 inches.

b. for every 1-inch increase in height, walking speed increases by 4.1 m/min.
c. for every 1 m increase in distance walked, walking speed
increases by 4.1 m/min.

d. for every 1-minute increase in walking time, walking speed
increases by 4.1 m/min.