1. The problem is to find the Interquartile Range (IQR) of a data set. 2. The IQR is a measure of statistical dispersion and is calculated as the difference between the third quartile ($Q_3$) and the first quartile ($Q_1$). 3. The formula for IQR is: $$\text{IQR} = Q_3 - Q_1$$ 4. To find $Q_1$ and $Q_3$, first arrange the data in ascending order. 5. $Q_1$ is the median of the lower half of the data (not including the median if the number of data points is odd). 6. $Q_3$ is the median of the upper half of the data. 7. Once $Q_1$ and $Q_3$ are found, subtract $Q_1$ from $Q_3$ to get the IQR. 8. The IQR represents the range within which the middle 50% of the data lies, helping to understand the spread and identify outliers.