What is one drawback of using the range as a measure of variability?

What is one drawback of using the range as a measure of variability?

• A. It is always equal to the standard deviation
• B. It is insensitive to extreme scores
• C. It can be influenced by extreme scores
• D. It has the smallest possible range

Answer: (C)

The range measures variability by looking at the distance between the highest and lowest values. A key drawback is that it can be influenced by extreme scores because it depends only on those two endpoint values. An outlier on the high or low end can dramatically widen or narrow the range, even if the rest of the data are tightly clustered. This makes the range a harsh and often misleading summary of dispersion, especially with small samples or skewed data. For example, if most scores are around 50 but one is 300, the range becomes 250, suggesting a much larger spread than is typical for the bulk of the data. In contrast, measures like the standard deviation incorporate all data points and describe average deviation from the mean, so they’re less swayed by a single extreme value.

The range measures variability by looking at the distance between the highest and lowest values. A key drawback is that it can be influenced by extreme scores because it depends only on those two endpoint values. An outlier on the high or low end can dramatically widen or narrow the range, even if the rest of the data are tightly clustered. This makes the range a harsh and often misleading summary of dispersion, especially with small samples or skewed data. For example, if most scores are around 50 but one is 300, the range becomes 250, suggesting a much larger spread than is typical for the bulk of the data. In contrast, measures like the standard deviation incorporate all data points and describe average deviation from the mean, so they’re less swayed by a single extreme value.