Term

Coefficient

Standard Error

Students’ t test

Probability > |t|

Intercept

3.65

0.19

19.74

<0.0001

X₁

−0.13

0.11

−1.15

0.3033

X₂

−0.16

0.11

−1.38

0.2265

X₃

−0.99

0.11

−8.77

0.0003

X₁X₂

0.12

0.16

0.73

0.4965

X₁X₃

0.17

0.16

1.04

0.3439

X₂X₃

−0.05

0.16

−0.31

0.7677

X₁²

−0.03

0.17

−0.20

0.8458

X₂²

−0.09

0.17

−0.52

0.6256

X₃²

0.94

0.17

5.65

0.0024