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FRM Part I · FRM Exam Part I · Linear Regression

A simple regression of Y on X has sample standard deviation of residuals (standard error of regression) of 4.0 with n = 52 observations, giving the variance of the slope estimator as s²/Σ(Xi − X̄)². If Σ(Xi − X̄)² = 400, what is the standard error of the slope estimate (use the residual variance s² = 16 directly)?

The slope variance equals residual variance divided by the sum of squared deviations of X: 16 divided by 400 is 0.04. The standard error is the square root of that, which is 0.20. Reporting 0.04 would confuse variance with standard error.

  1. A0.04
  2. B0.20Correct
  3. C0.80
  4. D0.16

Explanation

Var(b) = s²/Σ(Xi−X̄)² = 16/400 = 0.04. Standard error = √0.04 = 0.20. Option 0 reports the variance instead of its square root; option 2 uses 4/√25-type confusion using s/√... incorrectly.

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