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 />