vus_np1: First nonparametric estimation method of VUS
In toduckhanh/adjVUS: Adjusted-VUS

vus_np1 computes covariate-specific estimates of the VUS by using integrate with approximated distribution.

1	vus_np1(mu, sig, errors, ...)

`mu`	a vector of three estimated conditional means for given covariate's value.
`sig`	a vector of three estimated conditional variances for given covariate's value.
`errors`	a list of three estimated errors in regression models.
`...`	additional arguments supplied to the `npudist()` and `npudens()` functions.