Financial Risk Manager Part 1

Financial Risk Manager Part 1

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What is the difference between the biased and unbiased estimators of the variance?

TTanishq



Explanation:

The correct answer is C (5,767.49) as explicitly stated in the text.

Explanation of Biased vs Unbiased Variance Estimators:

  • Biased estimator of variance uses the formula: Οƒbiased2=βˆ‘i=1n(xiβˆ’xΛ‰)2n\sigma^2_{biased} = \frac{\sum_{i=1}^n (x_i - \bar{x})^2}{n} This is biased because it systematically underestimates the population variance.

  • Unbiased estimator of variance uses Bessel's correction: Οƒunbiased2=βˆ‘i=1n(xiβˆ’xΛ‰)2nβˆ’1\sigma^2_{unbiased} = \frac{\sum_{i=1}^n (x_i - \bar{x})^2}{n-1} This corrects for the bias by dividing by (n-1) instead of n.

The difference between these estimators is: Οƒunbiased2βˆ’Οƒbiased2=βˆ‘i=1n(xiβˆ’xΛ‰)2n(nβˆ’1)\sigma^2_{unbiased} - \sigma^2_{biased} = \frac{\sum_{i=1}^n (x_i - \bar{x})^2}{n(n-1)}

In this specific question, the numerical difference is given as 5,767.49.

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