Which term refers to the measure of variability that captures the range of the middle half of data values?

The term that refers to the measure of variability capturing the range of the middle half of data values is indeed the Interquartile Range (IQR). This statistic is specifically defined as the difference between the first quartile (Q1) and the third quartile (Q3) in a data set. It represents the spread of the middle 50% of the data, effectively providing insight into the central portion of the data distribution while minimizing the influence of outliers or extreme values. By focusing on the interquartile range, analysts can obtain a clearer understanding of the data's variability, leading to better interpretations of its overall distribution.

While the range signifies the difference between the maximum and minimum values, it does not focus solely on the central tendency. Standard deviation and variance measure how much individual data points differ from the mean, rather than focusing on the specific range of the middle half of the data. Thus, the IQR is the most suitable measure when one is interested in the variability concentrated around the center of the data.