6.1 Standard Deviation of a Normal Distribution
6.1 Standard Deviation of a Normal Distribu-
tion
Here you’ll learn the meaning of normal distribution and observe the pattern of its bell-shape. You’ll also learn how
to estimate the mean and the standard deviation of a normal distribution.
What do you think the average height is for people all over the world? If you were able to measure the heights of 500
people how do you think that graph would look? What do you think the average height would be? Has the average
height of the global population changed in the last 50 years?
Watch This
First watch this video to learn about the spread of a normal distribution.
MEDIA
Click image to the left for more content.CK-12 Foundation: Chapter6SpreadofaNormalDistributionA
Then watch this video to see some examples.
MEDIA
Click image to the left for more content.CK-12 Foundation: Chapter6SpreadofaNormalDistributionB
Guidance
Let’s go back to the basketball example presented in the introduction to this set of Concepts. When you made the
observations regarding the measurements of the diameter of the basketball, you must have noticed that they were
not all the same. In spite of the different measurements, you should have seen that the majority of the measurements
clustered around the value of 9.4 inches. This value represents the approximate diameter of a basketball. Also, you
should have noticed that a few measurements were to the right of this value, and a few measurements were to the
left of this value. The resulting shape looks like a bell, and this is the shape that represents anormal distribution
of data.