Whenever a statistical population can be described, at least roughly, by the perfectly symmetrical, bell-shaped normal curve, we can estimate the percentages of all population values that lie within specified numbers of standard deviations from the mean with the help of:
A) Tchebysheff's Theorem
B) the empirical rule
C) the interquartile range
D) box plot
E) none of these

Question

Quizplus · Accepted Answer

The empirical rule states that in a normal distribution, approximately 68% of the population falls within one standard deviation of the mean, 95% falls within two standard deviations, and 99.7% falls within three standard deviations. Therefore, it allows us to estimate the percentages of all population values that lie within specified numbers of standard deviations from the mean.

Whenever a Statistical Population Can Be Described, at Least Roughly