pScore: Prefit Model Score Test
In zrmacc/LiST: Linear Score Tests

Performs a joint score test on the covariates in G using a previously fit null model M0.

1	pScore(M0, G, X, method = "asymptotic", B = 1000, parallel = F)

`M0`	Prefit null model.
`G`	Covariates tested jointly for association with the outcome.
`X`	Model matrix used to fit `M0`.
`method`	Either "asymptotic" or "perturbation".
`B`	Score perturbations.
`parallel`	Run in parallel? Must reigster parallel backend first.

## Not run: 
Fit null model
M0 = Fit.LinReg(y=y,X=X);
# Matrix to test for association
G = matrix(rnorm(2e3),nrow=1e3);
# Prefit model score test
pScore(M0=M,G=G,X=X);
# Standard score test
Score(y=y,X=cbind(X,G),L=c(rep(F,ncol(X)),rep(T,ncol(G))));

## End(Not run)