The Empirical Rule applies to which type of distributions?

The Empirical Rule applies to which type of distributions?

• A. Skewed distributions
• B. Symmetric and unimodal distributions
• C. Uniform distributions
• D. Bimodal distributions

Answer: (B)

The Empirical Rule describes how data spread around the mean for distributions that look like a bell curve. It applies when the distribution is symmetric and unimodal—having a single peak and balanced on both sides of the center. In that case, about 68% of observations lie within one standard deviation of the mean, about 95% within two, and about 99.7% within three. If the distribution is skewed, flat (uniform), or has multiple peaks (bimodal), the rule doesn’t apply in the same simple way. So the best match is a symmetric and unimodal distribution.

The Empirical Rule describes how data spread around the mean for distributions that look like a bell curve. It applies when the distribution is symmetric and unimodal—having a single peak and balanced on both sides of the center. In that case, about 68% of observations lie within one standard deviation of the mean, about 95% within two, and about 99.7% within three. If the distribution is skewed, flat (uniform), or has multiple peaks (bimodal), the rule doesn’t apply in the same simple way. So the best match is a symmetric and unimodal distribution.