2.11.A—Describe a normal distribution

Describe a normal distribution.

• A continuous random variable is a variable that can take on any value within a specified domain. Every interval within the domain has a probability associated with it.
• Many continuous random variables are wellmodeled by a normal distribution.
• A normal distribution can be described as a continuous, unimodal, bell-shaped, and symmetric curve.
• A normal curve can be used to model a distribution of data and a continuous random variable.
• The normal distribution, or the normal curve, is identified by two parameters, the mean, µ, and the standard deviation, σ. The smaller the standard deviation, the taller and more concentrated the normal curve is around its mean. The larger the standard deviation, the shorter and less concentrated the normal curve is around its mean.