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FRM Part I · FRM Exam Part I · Linear Regression

In a regression of 27 observations, the estimated slope is 0.60 and the test of H0: slope = 0 gives a t-statistic of 2.50. The two-sided 5% critical t-value with 25 degrees of freedom is 2.06. What is the 95% confidence interval for the slope, and is zero inside it?

The standard error is 0.60 divided by 2.50, or 0.24. Multiplying by 2.06 gives a margin of about 0.49, so the interval is roughly 0.11 to 1.09. Zero lies outside it, consistent with rejecting the null of no relationship.

  1. A0.0 to 1.20 roughly, specifically 0.0 to 1.20 including zero
  2. B0.085 to 1.115; zero is outsideCorrect
  3. C0.60 to 1.115; zero is outside
  4. D0.085 to 1.115; zero is inside

Explanation

SE = 0.60/2.50 = 0.24. Margin = 2.06 × 0.24 = 0.4944. Interval = 0.6 ± 0.4944 = 0.106 to 1.094. Rounded, this is about 0.11 to 1.09, and zero is outside, consistent with t = 2.50 > 2.06. Option 2 is the closest, and it correctly concludes that zero lies outside.

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