Standard Normal Distribution

The standard normal distribution is a normal distribution with a mean of zero and a standard deviation of one.

Below is the graph of the standard normal distribution.

The curve appears to touch the horizontal axis (or z-scale) but in fact never does.

When we worked with the density curve for the unform distribution, it was very easy to see that the area under the curve was one since we had to find the area of a rectangle. To show that the area under the standard normal is one requires more advanced math. We will use tables and technology to get needed areas in the course.