Step 1: Write down the data set: 1, 2, 3, 4, 5, 6, 7, 8.
Step 2: Arrange the data in order (it is already in order).
Step 3: Find the median of the data set. The median is the middle number. Since there are 8 numbers, the median is the average of the 4th and 5th numbers: (4 + 5) / 2 = 4.5.
Step 4: Divide the data set into two halves. The lower half is 1, 2, 3, 4 and the upper half is 5, 6, 7, 8.
Step 5: Find Q1 (the median of the lower half). The lower half is 1, 2, 3, 4. The median is (2 + 3) / 2 = 2.5.
Step 6: Find Q3 (the median of the upper half). The upper half is 5, 6, 7, 8. The median is (6 + 7) / 2 = 6.5.
Step 7: Calculate the interquartile range (IQR) by subtracting Q1 from Q3: IQR = Q3 - Q1 = 6.5 - 2.5 = 4.
