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GATE 2025 ST – Question 61

Estimation · Point Estimation and Consistency · 2 marks · Numerical answer

Seven iid observations have density (λ³x²/2)e^(−λx),x>0,λ>0 unknown. The MLE λ̂ has bias E(λ̂−λ)=αλ. Find 1/α (integer).

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Correct answer: 20 to 20

Explanation

The sample sum S is gamma with shape 21,rate λ. The likelihood gives λ̂=21/S, and E(1/S)=λ/(21−1)=λ/20. Thus Eλ̂=21λ/20 and bias=λ/20, so α=1/20 and **1/α=20**.

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