Estimate Std.

Error

t value

Pr(>|t|)

(Intercept)

38.8797135

3.0568097

12.719

<2e−16

as.factor(cyl)4

7.2195952

2.1036081

3.432

0.000664

as.factor(cyl)5

9.2635725

3.1611670

2.930

0.003588

as.factor(cyl)6

3.4582042

2.3390418

1.478

0.140104

as.factor(cyl)8

6.0961268

2.7080015

2.251

0.024942

hp

−0.0673907

0.0163484

−4.122

4.60e−05

disp

−0.0008322

0.0086455

−0.096

0.923364

weight

−0.0043707

0.0007889

−5.540

5.63e−08

acc

−0.0828389

0.1197356

−0.692

0.489452