I am using VGAM package to model a multinormial outcome with spline
function. But from the following result, I only can get p-value for variable
with spline function, such as s(As). However, there is no p-value available
for variable with linear function, such as SEX, Parity. Does anybody know
why?


> summary(fit1)
Call:
vgam(formula = mr~ s(As) + s(Pb) + SEX + parity,
    family = "multinomial", data = paper)

Number of linear predictors:    3

Names of linear predictors: log(mu[,1]/mu[,4]), log(mu[,2]/mu[,4]),
log(mu[,3]/mu[,4])

Dispersion Parameter for multinomial family:   1

Residual Deviance:  3292.768 on 6423.567 degrees of freedom

Log-likelihood: -1646.384 on 6423.567 degrees of freedom

Number of Iterations:  10

DF for Terms and Approximate Chi-squares for Nonparametric Effects

              Df Npar Df Npar Chisq  P(Chi)
(Intercept):1  1
(Intercept):2  1
(Intercept):3  1
s(As):1        1     2.2     1.5061 0.51558
s(As):2        1     2.8     3.7633 0.26187
s(As):3        1     3.8     1.8600 0.74002
s(Pb):1        1     2.4     7.7796 0.03172
s(Pb):2        1     2.8     8.5664 0.03091
s(Pb):3        1     3.3     5.6044 0.16036
SEX:1         1
SEX:2         1
SEX:3         1
parity:1       1
parity:2       1
parity:3       1


Thanks a lot.
Weichao

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