Which term best describes measures such as median and IQR in relation to data variability?

The term that best describes measures such as median and interquartile range (IQR) in relation to data variability is robust. Robust statistics are those that are not strongly influenced by outliers or non-normal distributions. The median is the middle value when data is arranged in order and is less affected by extreme values than the mean, making it a robust measure of central tendency. Similarly, the IQR—which measures the spread of the middle 50% of the data—is also not influenced by outliers, as it focuses on the range between the first and third quartiles.

This characteristic of robustness makes the median and IQR particularly useful when dealing with skewed data or datasets that might contain outliers, as they provide a clearer picture of central tendency and variability without being distorted by extreme values. Other terms such as skewed (which describes the asymmetry of a distribution), parametric (which refers to methods that assume a specific distribution), and non-parametric (which refers to methods that do not assume a specific distribution) do not capture this key aspect of the measures being discussed.