Think it depends on sample size since de Moivre’s equation is : {\mathop{\rm\sigma}} \left( {\bar x} \right) = \frac{{\sigma }} {\sqrt n}

where {\mathop{\rm\sigma}} \left( {\bar x} \right) is the standar error of the mean, {\mathop{\rm\sigma}} is the standard deviation of the sample and n is the size of the sample.

A very small sample size will show high variance and may produce spurious numbers not representative of the entire population as a whole.