The range and interquartile range are two important statistical measures used to describe the spread or dispersion of a set of data. Let's dive into each concept and explore how they are calculated.

Range: The range is simply the difference between the highest and lowest values in a dataset. For example, consider the following set of test scores: 75, 82, 90, 88, 92, 70. To find the range, subtract the lowest value (70) from the highest value (92). The range in this case is 92 - 70 = 22.

Interquartile Range (IQR): The interquartile range represents the spread of the middle 50% of the data. It is calculated by subtracting the first quartile (Q1) from the third quartile (Q3). To understand this, we need to determine the quartiles first.