Quantile Plots in Machine Learning

A quantile plot is a simple and effective way to have a first look at a univariate data distribution> First, it displays all of the data for the given attribute. Second, it plots quantile information. The mechanism used in this step is slightly different from the percentile computation. Let Xi , for i=1 to N. be the data sorted in increasing order so that X1 is the smallest observation and Xn is the largest. Each observation, Xi, is paired with a percentage, Fi, which indicates that approximately 100 Fi% of the data are below or equal to the value, Xi. We say 'approximately' because there may not be a value with exactly a fraction, Fi, of the data below of equal to Xi,  Fig, shows a quantile plot for the unit price data of the table