How do you find what the IQR

Find the median (the middle number).

Find both the upper and lower quartile.

Then subtract the upper quartile from the lower quartile and you get the fianl answer.

For example:

1, 12, 16, 23, 34, 54, 72

median: 23

lower quartile: 12

upper quartile: 54

(IQR) interquartile range: 54 - 12 = 42

We get the interquartile range of 42.

Bow hello IQR is 21 + 1 - 1 = 21