## Empirical Rule and z-score Probability

Empirical Rule The Empirical Rule applies to a normal, bell-shaped curve than is symmetrical about the mean. It states that within one standard deviation of the mean (both left-side and right-side) there is about 68% of the data; within two standard deviations of the mean (both left-side and right-side) there is about 95% of the data; […]

## Normal Distribution: Example Problem 1

One way to improve your ability to solve normal distribution problems is to work on recognizing what word problems are requesting you to do. Consider the following problem statement: In an investigation of the personality characteristics of drug dealers of a certain region, convicted drug dealers were scored on a scale that provides a quantitative […]