CORRECT TEXT

CORRECT TEXT

The standard error of a Monte Carlo simulation is:
A . Zero
B . The same as that for a lognormal distribution
C . Proportional to the inverse of the square root of the sample size
D . None of the above

View Answer

Answer: C

Explanation:

When we do a Monte Carlo simulation, the statistic we obtain (eg, the expected price) is an estimate of the real variable. The difference between the real value (which would be what we would get if we had access to the entire population) and that estimated by the Monte Carlo simulation is measured by the ‘standard error’, which is the standard deviation of the difference between the ‘real’ value and the simulated value (ie, the ‘error’).

As we increase the number of draws in a Monte Carlo simulation, the closer our estimate will be to the true value of the variable we are trying to estimate. But increasing the sample size does not reduce the error in a linear way, ie doubling the sample size does not halve the error, but reduces it by the inverse of the square root of the sample size. So if we have a sample size of 1000, going up to a sample size of 100,000 will reduce the standard error by a factor of 10 (and not 100), ie, SQRT(1/100) = 1/10. In other words, standard error is proportional to 1/N, where N is the sample size.

Therefore Choice ‘c’ is correct and the others are incorrect.