how do you identify an outlier
Hi, You have 10 data points and hence from the bottom 5 you get a lower quartile of Q 1 = 89 and an upper quartile of Q 3 = 99. Hence the box extends from 89 to 99 and the interquartile range IQR is 99 - 89 = 10. An outlier is any data point that is more than 1.5 times the IQR from either end of the box. 1.5 times the IQR is 1.5 10 = 15 so, at the upper end an outlier is any data point more than 99 + 15 = 114.