Tukey 's Biwelght A popular ( psi ) function for robust regression is Tukey 's biweight, where psi(z) begin cases z left 1 (z a) 2 ight 2 , z leq a 0, z a end cases with (a 5 ) Sketch the ( psi ) function for (a 5 ) and discuss its behavior Do you think that Tukey 's biweight would give results sim...

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Tukey's Biwelght. A popular (psi) function for robust regression is Tukey's biweight, where [ psi(z)= begin{cases}zleft[1-(z /

Question:

Tukey's Biwelght. A popular \(\psi\) function for robust regression is Tukey's biweight, where

\[
\psi(z)= \begin{cases}z\left[1-(z / a)^{2}\right]^{2}, & |z| \leq a \\ 0, & |z|>a\end{cases}
\]

with \(a=5\). Sketch the \(\psi\) function for \(a=5\) and discuss its behavior. Do you think that Tukey's biweight would give results similar to Andrews' wave function?