Hi,
I am reading the book "Mixed Effects Models in S and S-Plus" and come
across an example with the Rail data.
I tried to use lm(travel~Rail,data=Rail) and got the following result:

Call:
lm(formula = travel ~ Rail, data = Rail)

Residuals:
    Min      1Q  Median      3Q     Max
-6.6667 -1.0000  0.1667  1.0000  6.3333

Coefficients:
            Estimate Std. Error t value Pr(>|t|)
(Intercept)  66.5000     0.9477  70.169  < 2e-16 ***
Rail.L       54.3032     2.3214  23.392 2.22e-11 ***
Rail.Q       -4.6917     2.3214  -2.021 0.066161 .
Rail.C       -2.6584     2.3214  -1.145 0.274458
Rail^4       -0.5669     2.3214  -0.244 0.811181
Rail^5       11.1919     2.3214   4.821 0.000418 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1


I wonder how the model is represented. Is it correct to write: Travel =
beta1 + beta2*Rail + error? Beta1 should be Intercept which is clear to me.
But how to link beta2 with the coefficients Rail.L, Rail.Q, Rail.C, Rail^4
and Rail^5 shown in the result?

Thanks for your comments,

Best,
Jing

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