Question

given the regression line y=42-3x what number of units are expected to increase in y if x is decreased by 2 units.
a)2
b)4
c)6
d)8

Answer 1

The change is caused by the term -3x

Since you are "decreasing" x by 2
we sub in x = -2
so y = 42 - 3(-2) = 42 + 6
thus the change is 6

Answer 2

y = -1 x +42

slope = -1 = change in y/change in x
if
change in x - -1
then
change in y /-2 = -1
so
change in y = -1 (-2)
= +2

Answer 3

-3(-2) = +6

Answer 4

thanks got it