2. Learning Objectives
After completing this vignette, a student should be able to:
• Describe the elements of a normal distribution. What is needed to
construct one?
• Recognize the normal probability distribution and apply it appropriately
• Demonstrate the use of a probability distribution
3.
4. Normal Distribution: a specific type of probability distribution, where the
mean, median, and mode are centered around the middle.
Distribution depends on the mean and standard deviation
5.
6. Other names for a Normal Distribution
Gaussian Distribution
The “Bell Curve”
14. Let’s try it!
A pizza festival predicts that annual sales will have a mean of $120,000
and will be normally distributed with a standard deviation of $30,000.
Approximately what percent of
years that their annual
pizza sales will yield less than
$90,000?
15. Approximately 16% of yearly pizza sales will be less than
$90,000.
How did we find this answer?
By shading in the area that was less than 90 and adding all the percentages
within that area together.
13.5% + 2.35% + 0.15% = 16%
or
(100% - 68%)/2 = 16%
16. Take Home Messages!
Normal distribution allows us to understand how data values very for
they describe how likely it is that any value will occur
The greatest frequency will occur in the middle and smaller extreme
values will be found at the tail end of the distribution
