Asked by jake

Suppose x is a random variable with mean and standard deviation. If a large number of trials is observed, at least what percentage of these values is expected to lie beween mean-2(standard deviation) and mean + 2(standard deviation)

could someone help me i'm so lost? thank you sooooo much!!!
Answered by bobpursley
Memorize it. Two standard deviations contain 95 percent of the population.