Probability and statistics: Interquartile range (IQR)
Step 1: Put the numbers in order
Step 2: Find the median (How to find a median)
Step 3: Place parentheses around the numbers above and below the median.
Not necessary statistically–but it makes Q1 and Q3 easier to spot.
Step 4: Find Q1 and Q3
Q1 can be thought of as a median in the lower half of the data, and Q3 can be thought of as a median for the upper half of data.
(1,2,5,6,7), 9, ( 12,15,18,19,27). Q1=5 and Q3=18.
Step 5. Subtract Q1 from Q3 to find the interquartile range.