Class: 1,2,3,3,4,4,4,4,5,3
First, order from lowest to highest
1,2,3,3,3,4,4,4,4,5
Median = (1,2,3,3) 3, 4,(,4,4,4,5) = (3+4)/2 = 3.5
Find the median of the first and last half:
Q1 = 1,2,3,3,3.5 = 3
Q3 = 3.5,4,4,4,5 = 4
Then for the interquartile: Q3- Q1 = 4 -3 = 1