Which measure would you use to describe the spread of data around the median?

Which measure would you use to describe the spread of data around the median?

• A. Range
• B. Standard Deviation
• C. Interquartile Range
• D. Variance

Answer: (C)

Interquartile range captures how far the middle portion of the data is spread around the median. It looks at the range between the first and third quartiles (Q1 to Q3), so it describes the dispersion of the central 50% of values. This focus on the middle, rather than the extremes, makes it robust to outliers that could skew other measures. The other measures don’t describe spread around the median as effectively. The range stretches from minimum to maximum and can be driven by a single extreme value, giving a misleading sense of overall dispersion. The standard deviation and variance measure how far data are dispersed around the mean, not the median, and they can be distorted by skewness or outliers. So when the center of interest is the median, the interquartile range is the best descriptor of spread.

Interquartile range captures how far the middle portion of the data is spread around the median. It looks at the range between the first and third quartiles (Q1 to Q3), so it describes the dispersion of the central 50% of values. This focus on the middle, rather than the extremes, makes it robust to outliers that could skew other measures.

The other measures don’t describe spread around the median as effectively. The range stretches from minimum to maximum and can be driven by a single extreme value, giving a misleading sense of overall dispersion. The standard deviation and variance measure how far data are dispersed around the mean, not the median, and they can be distorted by skewness or outliers. So when the center of interest is the median, the interquartile range is the best descriptor of spread.