In descriptive statistics, the interquartile range<span> (</span>IQR<span>), also called the midspread or middle 50%, or technically H-spread, is a measure of statistical dispersion, being equal to the difference between 75th and 25th percentiles... ~ wikipedia
according to Wikipedia and some quick mental math the answer would be four
four is the difference between 14 and 18 which are respectively the 25th and 75th percentiles.</span><span />
The interquartile range is the difference between the third quartile, Q3, and the first quartile, Q1.
In a box plot, Q1 makes up the left hand side of the box and Q3 makes up the right hand side of the box. In this figure, Q1 is 14 and Q3 is 18; this makes the IQR