Inter-quartile Range

iqr(input: any[] | Mat | Tensor) : Number

param input a JS array, matrix or tensor, or a series of numbers, to find the inter quartile range of

returns - Number - a number representing the inter quartile range.

The interquartile range, or the midspread or middle 50%, is the difference between the 75th and 25th percentiles of the data. So this function is taking data from a construct, whether it is a series of numbers, a declared array, Mat, or Tensor and finds the 75% and 25% percentiles, namely 'q1' and 'q3', the 1st and 3rd quantiles for 0.25 and 0.75. Then we return q3-q1 to end up with the iqr or midspread or middle 50%, or q2.