What is the outlier in this data set:

1,2,2,3,3,3,3,4,9

Q1: first quartile:
9(.25) = 2.25
Q1=x[3] = 2
9(.75)= 6.75
Q3=x[7]=3
Inter-quartile range =Q3-Q1 = 3-2 = 1
IQR = Inter-quartile range = Q3-Q1

Compute Lower fence = Q1-1.5(IQR)
2-1.5(1) =0.5
Upper fence = Q3+1.5(IQR)
3+1.5(1) = 4.5
Any data lying outside the bound (L,U) can be considered an outlier
outside of (0.5, 4.5) , the value is 9

9