The 68–95–99.7 rule tells us how to find the middle 68%, 95% or 99.7% of a normal distribution. Suppose we wanted to find numbers A and B, so that the middle 80% of a standard normal distribution lies between A and B, where A is less than B. One of the answers below is NOT true of A and B. Which answer is NOT true?
Twenty percent of the distribution lies below A. 0 To get the middle 80%, we would have A = -B. 3 B is approximately 1.28 Ten percent of the distribution lies above B.