Skip to content

FRM Part I · FRM Exam Part I · Common Univariate Random Variables

Let X be uniform on [a, b] with mean 50 and variance 75. What is the value of b?

The upper bound b is 65. The mean of 50 implies a+b = 100, and the variance of 75 implies (b-a)^2 = 900, so b-a = 30. Solving gives a = 35 and b = 65.

  1. A60Correct
  2. B65
  3. C70
  4. D80

Explanation

Mean gives a+b = 100. Variance gives (b-a)^2 = 75 x 12 = 900, so b-a = 30. Then b = (100+30)/2 = 65, a = 35. Check: 30^2/12 = 75. Hence 65.

Did you get it right without looking?

One question tells you little. A timed set on Common Univariate Random Variables shows your real accuracy, how long you take and where you lose marks.

Practise Common Univariate Random VariablesFree diagnostic mock

More Common Univariate Random Variables questions