Now that we have determined Q1 and Q3, we can calculate the interquartile range (IQR). Using our test scores example, Q1 = 75 and Q3 = 90. Subtracting Q1 from Q3 gives us the interquartile range: IQR = 90 - 75 = 15.

The IQR provides insight into the dispersion of the middle 50% of the data. A larger IQR indicates greater variability, while a smaller IQR suggests a more concentrated data set.

Remember, the range and interquartile range are valuable tools that help us understand the spread of data. Practice calculating them with different data sets to strengthen your grasp of these concepts.