# Probable Error

The term probable error is seen only in older statistics literature where it used to denote the product of the standard error and a constant factor 0.6745. Thus,

$P.E = 0.6745\,\left( {S.E} \right)$

Here P.E and S.E stand for the probable error and the standard error, respectively. By using the above formula the probable error of any statistic may be determined if we substitute the standard error of that statistic. Hence, for example, the probable error of the correlation coefficient would be
$P.E = 0.6745\,\sqrt {\frac{{1 – {\gamma ^2}}}{n}}$

Nowadays probable error is not in common use.