If z^2 is directly proportional to W and Z=4 when W=8

The constant of proportionality is 2.

Step-by-step explanation:

z^2 = kW   where k is a constant.

When z = 4 , W = 8 so

4^2 = 8k

k = 4^2/8

= 16/8

= 2.

1.4

2.3

step-by-step explanation:

the formula for the constant of variation is

y= kx

divide each side by x

y/x =kx/x

y/x =k

we know a and y

1.   y/x = k

4/1 =4

check the other values to make sure they are the same

8/2 = 4   12/3 =4   and 16/4 =4  

the constant of variation is 4

2.   y/x = k

3/1 =3

check the other values to make sure they are the same

6/2 = 3   9/3 =3   and 12/4 =3  

the constant of variation is 3

a. the residual plot for model 1 has a random pattern and is a good fit for the data.