What is the interquartile range (IQR)?

The interquartile range (IQR) is defined as the range of the middle 50% of data points in a dataset. It is calculated by subtracting the first quartile (Q1), which represents the 25th percentile, from the third quartile (Q3), which represents the 75th percentile. This measure effectively captures the spread of the central portion of the data, allowing for a summary of variability that is less influenced by extreme values or outliers than the overall range.

The IQR is particularly useful in descriptive statistics because it provides insight into the distribution and dispersion of the data, focusing specifically on the central half, which is often the most relevant for understanding typical values within the dataset. This makes option B the correct answer because it accurately describes the essence of what the interquartile range represents.