Let w be an unbiased estimate of an unknown w∈R. Given a function t(w), we show how to choose a function fn​(w) such that for w∗=w+fn​(w), E t(w∗)=t(w). We illustrate this with t(w)=wa for a given constant a. For a=2 and w normal, this leads to the convolution equation cr​=cr​⊗cr​
Let w be an unbiased estimate of an unknown w∈R. Given a function t(w), we show how to choose a function fn​(w) such that for w∗=w+fn​(w), E t(w∗)=t(w). We illustrate this with t(w)=wa for a given constant a. For a=2 and w normal, this leads to the convolution equation cr​=cr​⊗cr​