weighted_len: Weighted length of a confidence band
In koohyun-kwon/HTEBandSim: What the Package Does (One Line, Title Case)

Computes weighted length of a confidence band, where the weights are given by the design of the regressor.

1	weighted_len(eval, cb.l, cb.u, x.spec = c("unif", "beta"))

`eval`	a vector of evaluation points in the support of the regressor
`cb.l`	a vector of lower confidence band values
`cb.u`	a vector of upper confidence band values
`x.spec`	distribution of the regressor, which determines the weights. Supports the uniform distribution (`"unif"`) and the normalized beta(2, 2) distribution (`"beta"`), both with the support of [-1, 1].