Increasing Accuracy

Consider an economist at the Federal Reserve Bank is trying to estimate the mean (M) of household incomes in the US from a sample size (n) randomly surveyed from the population. From the sample data, the standard deviation is "s", and the mean is "x". Increasing which of the below variables will produce greater accuracy for the study?
  1. M+S
  2. s
  3. n
  4. M

Hint
Increased data points will help with accuracy.
Accuracy increases with increasing sample size. The correct variable is "n" (option 3).
Option 3