The accompanying data file contains 20 observations on the response variableyalong with the predictor variablesx,d₁, andd₂.

Click here for the Excel Data File

a.Estimate a regression model with the predictor variablesx,d₁, andd₂, and then extend it to also include the interaction variabled₁d₂. What is the estimated regression coefficient for the predictor variablexin both models?(Negative values should be indicated by a minus sign. Round your answers to 2 decimal places.)

b-1.Which is the preferred model for making predictions?

b-2.Use the preferred model to predicty.(Round coefficient estimates to at least 4 decimal places and final answers to 2 decimal places.)

y	x	d1	d2
36	16	0	0
31	18	1	1
29	8	0	0
33	11	0	1
31	6	1	0
26	15	0	0
39	14	0	0
26	18	0	1
16	8	1	1
1	12	0	1
28	22	0	0
17	7	0	0
30	14	0	0
49	25	1	1
35	6	1	0
45	16	1	1
23	14	0	1
2	8	0	1
29	16	0	0
51	16	1	0