Suppose that you have two independent unbiased estimators of the same parameter , say 1 and

Suppose that you have two independent unbiased estimators of the same parameter θ̂, say θ̂₁ and θ̂₂, with different variances v₁ and v₂. What linear combination θ̂ = c₁ θ̂₁ + c₂ θ̂₂ is the minimum variance unbiased estimator of θ?