Answer
IQR = Q3 - Q1
Upper fence value = Q3 + (1.5×IQR)
Lower fence value = Q1 - (1.5×IQR)
Work Step by Step
a. )Rearrange the values in ascending order: 13,13,14,14,15,15,16,20,21,26
The Median or Q3: (15 + 15)/2 = 15
Median of Lower Half Observations: 14
Median of Upper Half Observations: 20
b.) IQR = Q3 - Q1
IQR = 20 - 14 = 6
c.) Upper fence value = Q3 + (1.5×IQR)
= 20 + (1.5×6) = 29
An observation would have to be greater than 29 to be an outlier.