Third quartile plus 1.5 times the interquartile range (Q3 - Q1). The Q1, Q2, Q3 quartiles correspond to the 25th, 50th, and 75th percentiles. Q2 is also known a

Third quartile plus 1.5 times the interquartile range (Q3 - Q1). The Q1, Q2, Q3 quartiles correspond to the 25th, 50th, and 75th percentiles. Q2 is also known as the median.