Skewness Kurtosis
Skewness Rsk is a measure of the asymmetry of the amplitude density curve. A negative skewness value indicates a surface with good bearing properties.
Kurtosis Rku is a measure of the peakedness of the amplitude density curve. For a profile with a Gaussian amplitude density curve Rku is 3.
Skewness and Kurtosis are strongly influenced by isolated peaks and valleys, which reduces their practical importance.