i need help on determining if their is an outlier...i know how to find the median and the lower quartile and the upper quartile..but i don't understand about the outliers....please tell me if their is an outlier in this problem....the numbers are...63,88,89,89,95,98,99,99,100,100
thank you

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. There are no data points larger than 114 so there are no outliers at the upper end.
At the lower end an outlier is any data point less than 89  15 = 74. There is one data point, 63, which is less than 74 so 63 is an outlier.
I hope this helps.
Penny
