Hands-On Data Analysis with Pandas

Interquartile range

So far, other than the range, we have discussed mean-based measures of dispersion; now, we will look at how we can describe the spread with the median as our measure of central tendency. As mentioned earlier, the median is the 50^th percentile or the 2^nd quartile (Q₂). Percentiles and quartiles are both quantiles—values that divide data into equal groups each containing the same percentage of the total data; percentiles give this in 100 parts, while quartiles give it in four (25%, 50%, 75%, and 100%).

Since quantiles neatly divide up our data, and we know how much of the data goes in each section, they are a perfect candidate for helping us quantify the spread of our data. One common measure for this is the interquartile ...