About ______ of z-scores in the standard normal distribution are within ______ standard deviations of the mean.
A) 99%; ±1
B) half; ±2
C) two-thirds; ±3
D) 95%; ±2

Question

Quizplus · Accepted Answer

The Empirical Rule states that in a normal distribution, approximately 68% of the data falls within one standard deviation of the mean, 95% falls within two standard deviations of the mean, and 99.7% falls within three standard deviations of the mean. Since the standard normal distribution has a mean of 0 and a standard deviation of 1, approximately 95% of the z-scores fall within ±2 standard deviations of the mean.

About ______ of Z-Scores in the Standard Normal Distribution Are