There are 4 characteristics of standard normal distribution.

1.      It is bell shaped and the total area under the curve is equal to 1.00.

2.      It is symmetrical about the mean.

3.      The distribution is asymptotic (the curve gets close and closer to the x axis but never actually touches it) (Lind, et al., 2011).

4.      The location of a normal distribution is determined by the mean.  The dispersion of the distribution is determined by the standard deviation.

To calculate the z-test, the mean is subtracted from each observation, and then this difference is by the standard deviation.

An example of the z-value is to find the area under the distribution of P(0 to z) when z = 1.96.  To calculate this area, a table of the area under the normal curve is used.  The z score is found first by taking the first part of the z score (1.9) and find this value under the first column
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