Shrinkage estimator of the high-dimensional mean vector as suggested in
BOP2019;textualHDShOP. It uses the formula
$$\hat \mu_{BOP} = \hat \alpha \bar x + \hat \beta \mu_0,$$ where
\(\hat \alpha\) and \(\hat \beta\) are shrinkage coefficients given by
Eq.(6) and Eg.(7) of BOP2019;textualHDShOP that minimize
weighted quadratic loss for a given target vector \(\mu_0\)
(shrinkage target). \(\bar x\) stands for the sample mean vector.
Usage
mean_bop19(x, mu_0 = rep(1, p))
Value
a numeric vector containing the shrinkage estimator of
the mean vector
Arguments
x
a p by n matrix or a data frame of asset returns. Rows represent
different assets, columns -- observations.
mu_0
a numeric vector. The target vector used in the construction of
the shrinkage estimator.