statsmodels.robust.norms.TrimmedMean.rho

TrimmedMean.rho(z)[source]

The robust criterion function for least trimmed mean.

\[\begin{split}\rho(z) = \begin{cases} \frac{1}{2} z^2 & \text{for } |z| \le c \\ \frac{1}{2} c^2 & \text{for } |z| > c \end{cases}\end{split}\]
Parameters:
zarray_like

1d array

Returns:
rhondarray

The value of the robust criterion function.