Consider the estimated relationship: Y = 50 + 50X + 21Z Based on this regression equation, select all the statements which are True:
A.) Controlling for X, the value of Y decreases by 21 units for unit increase in Z
B.) The average value of Y when X=0 and Z=0 is 50.
C.) Controlling for Z, the value of Y increases by 50 units for 1 unit in X
D.) Controlling for X, the value of Y increases by 100 units for 1 unit increase in Z

20

step-by-step explanation:

50x5=$250

step-by-step explanation:

system of linear equation

step-by-step explanation:

as given in the data

a= 20 , b= -12

let us suppose that it is a straight line equation

now we know the formula for the system of linear equation

b= ma + c )

here m is slope of a straight line which is equal to formula

m=   (ii)

and here c is a constant

now putting the value of a and b in equation (ii)

m=

m=

putting the value of a,b and m in equation (i) gives us

-12 = + c

-12=-12 + c

adding 12 to both sides

-12 +12 = -12 +12 +c

0 =c

or c=0

as the value of the constant is zero which gives us that it is a linear equation and this order pair satisfies the system of linear equations.