posted by rachel .
The Russian mathmatician Pafnuti L. Chebychev pved a remarkable theorem called Chebybchev's Inequality: In any data set, if p is the fraction of the data that lies within k standard deviations to either side of the mean, then p is greater than or equal to 1-1/k^2.
a. According to Chebychev's Theorem, what percent of a data set must lie within 2 standard deviations of the mean?
b. What percent must lie within 3 standard deviations?