Problem
Given the following data set: 2, 5, 7, 9, 12, 15, 18, 21, 23, 25. Calculate the interquartile range.
Solution
Step 1 ：Step 1: First, we arrange the data in ascending order, which is already done.
Step 2 ：Step 2: Split the data into two halves. The lower half is: 2, 5, 7, 9, 12. The upper half is: 15, 18, 21, 23, 25.
Step 3 ：Step 3: Find the median of both halves. The median of the lower half (Q1) is 7. The median of the upper half (Q3) is 21.
Step 4 ：Step 4: Subtract Q1 from Q3 to find the interquartile range. \(Q3 - Q1 = 21 - 7 = 14\).
