I've come across two different forms of a skewness-adjusted t-statistic, which was developed originally by Johnson (1978): $ J = t + \frac{gt^2}{3n} + \frac{g}{6n} $
and $ J = t + \frac{gt^2}{3\sqrt{n}} + \frac{g}{6\sqrt{n}}, $
where $t$ is the conventional t-statistic, $n$ is the number of observations, and $g$ is the skewness estimate. The null hypothesis is zero mean.
Could you advise me what's difference between the two forms?
Many thanks, Dave