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Paired-return slope and intercept practice

These original questions use the supplied five-period record rather than official exam items.

Use the original paired data

Original hypothetical period returns
PeriodBenchmark (%)Asset (%)
1-2-3
2-1-0.5
301
412.5
526

Retain the fitting definitions

Benchmark mean is zero, asset mean 1.2%, Sxx=10 and Sxy=21 in percentage-point units. The line includes an intercept and uses equal observation weights.

Try the questions

What is the original asset-on-benchmark slope?

  • A.

    2.1

  • B.

    0.986666 approximately

  • C.

    70/151

Answer and explanation

Answer: A

Keep the explanatory return in the denominator.

A

21/10 uses the benchmark centered squared sum.

B

This is correlation, with a different denominator.

C

This is the reverse-regression slope.

Which covariance/variance pair reproduces the original slope?

  • A.

    5.25 / 2.5

  • B.

    5.25 / 2

  • C.

    4.2 / 2.5

Answer and explanation

Answer: A

A common divisor cancels in the ratio.

A

Both use the n−1 sample divisor.

B

This mixes sample covariance and population variance.

C

This mixes population covariance and sample variance.

A constant 0.1% is subtracted from both series. What is the new intercept?

  • A.

    1.2% automatically

  • B.

    1.31%

  • C.

    1.1%

Answer and explanation

Answer: B

Keep raw and excess-return bases distinct.

A

The slope remains the same, but the intercept shifts.

B

1.2%+(2.1−1)×0.1% uses the stated constant translation.

C

This is the new asset mean, not the excess intercept.

Further references