# Unbiased estimate of cross-product for unbiased vector

#### Leigh

##### New Member
Let g be an unbiased estimate of a vector G. Can g be used to find an unbiased estimate of the cross product GG′ (where G' is the transpose of G)? I'm stuck because naively using gg′ is a biased estimator, with the (upwards) bias depending on the noise in g.