In this paper we will propose two new estimators for sparse covariance matrix.Our starting point is to make the estimator of each element of covariance matrix more robust.
In this paper,we focus on the partially linear varying-coefficient quantile regression model when the data are right censored and the censoring indicators of right censored data are missing at random.
Hospitalizations account for one-third of the annual healthcare costs in the USA.A large percentage of hospital readmissions can be avoided or prevented.