In general, percentiles and quartiles are specific types of quantiles. Using quartiles, these optimal estimators can be approximated by the midhinge and the trimean. The IQR is a measure of variability, based on dividing a data set into quartiles. Afterwards, all the values are classified using quartiles. In order to calculate quartiles in Matlab, the function "quantile(A,p)" can be used. What are the 4-quantiles (the "quartiles") of this dataset? This disproportionately affected schools only serving the three less-able quartiles. The three-halfpence coins came to be called "quartiles" or "quatties". Quartiles divide a rank-ordered data set into four equal parts.