1. Statistics 3502/6304 Prof. Eric A. Suess Chapter 4

2. Normal Distribution The Normal distribution is the “bell shaped curve” The Normal distribution is a model for the common shape of the distribution of measurement variables seen in histograms. The model gives a mathematical way to compute probabilities.

3. Standard Normal Distribution The standard Normal distribution is the Normal distribution with mean parameter equal to 0 and the standard deviation equal to 1. The standard normal distribution is the reference distribution for all normal distribution. The standard normal distribution is like the Kelvin temperature scale for degrees F and degrees C. A temperature is the same on all scales, but Kelvin is the absolute temperature.

4. Z-score

5. Normal Probabilities To compute Normal probabilities, we can use the z-score and then use a Normal table or use Minitab. Example: Suppose temperatures on todays date are Normal distributed with mean 70 and standard deviation 5 degrees F. Find the probability that the temperature next year on this date with be greater than 80 degrees F.