​Statements about the proportion of data values that must be within a specified number of standard deviations of the mean can be made using

A) ​Chebyshev's theorem.
B) The empirical rule.
C) ​A five-number summary.
D) Percentiles.

Chebyshev's theorem is a general rule that can be applied to any data set, regardless of its shape or distribution. It states that for any data set, at least 1 - 1/k^2 of the data values must be within k standard deviations of the mean, where k is any positive integer greater than 1. This makes it a more versatile tool for making statements about the spread of data than the empirical rule, which only applies to bell-shaped distributions. The five-number summary and percentiles are useful for summarizing and comparing data sets, but they do not provide information about the proportion of values within a certain distance from the mean like Chebyshev's theorem does.