Tukey s Biwelght. A popular function for robust regression is Tukey s biweight, where with a = 5, 6 Sketch the

Tukey ’ s Biwelght. A popular ψ function for robust regression is Tukey ’ s biweight, where

with a = 5, 6 Sketch the ψ function for a = 5 and discuss its behavior. Do you think that Tukey ’ s biweight would give results similar to Andrews ’ wave function?

y(z)= [z[1-(z/a)], |z|a |z|> a