If a score distribution forms a normal curve,
A) each standard deviation above or below the mean will include a fixed percentage of scores.
B) the standard deviation can be calculated from the mean alone.
C) the median is a better measure of central tendency than the mean.
D) the mode is a better measure of central tendency than the mean.

Question

Quizplus · Accepted Answer

In a normal distribution, a fixed percentage of scores falls within each standard deviation from the mean. This property is fundamental to the definition of a normal curve, where approximately 68% of the data falls within one standard deviation of the mean, about 95% within two standard deviations, and about 99.7% within three standard deviations. This does not depend on the mean alone, and the mean, median, and mode are all equal in a perfectly normal distribution.

If a Score Distribution Forms a Normal Curve