Skip to content

NISM Certifications · NISM-Series-XV: Research Analyst · Fundamentals of Research

Monthly returns of a stock (in %) over five months are 2, 4, 6, 8 and 10. Treating these as the entire population, what is the standard deviation?

The population standard deviation is 2.83%. The mean is 6, the squared deviations sum to 40, dividing by 5 gives a variance of 8, and its square root is 2.83%. Using n-1 would wrongly give 3.16%.

  1. A2.00%
  2. B2.83%Correct
  3. C3.16%
  4. D6.00%

Explanation

Mean = 30/5 = 6. Deviations: -4, -2, 0, 2, 4; squares: 16, 4, 0, 4, 16 = 40. Population variance = 40/5 = 8; standard deviation = square root of 8 = 2.83%. The 3.16% figure comes from dividing by n-1 (sample, 40/4 = 10), which is wrong for a population. The 6% option is just the mean.

Did you get it right without looking?

One question tells you little. A timed set on Fundamentals of Research shows your real accuracy, how long you take and where you lose marks.

More Fundamentals of Research questions