Editing Chebyshev's inequality (section)

==Example==
Suppose we randomly select a journal article from a source with an average of 1000 words per article, with a standard deviation of 200 words. We can then infer that the probability that it has between 600 and 1400 words (i.e. within <math>k=2</math> standard deviations of the mean) must be at least 75%, because there is no more than <math>1/k^2 = 1/4</math> chance to be outside that range, by Chebyshev's inequality. But if we additionally know that the distribution is [[normal distribution|normal]], we can say there is a 75% chance the word count is between 770 and 1230 (which is an even tighter bound).