 A graphical approach is usually more informative than a formal statistical test and hence.a normal quantile plot is commonly used to assess the fit of a data set to a normal population.Alternatively, rules of thumb based on the sample skewness and kurtosis have also been proposed.If we observe a set of "n" values "X"1, ..., "X""n" with no ties (i.e., there are "n" distinct values), we can replace "X""i" with the transformed value "Y""i" = "k", where "k" is defined such that "X""i" is the "k"th largest among all the "X" values.