Normal Approximation of the Binomial
Lesson: NORMAL APPROXIMATION OF THE BINOMIAL
Concept/Topic
Understand the Normal Approximation of the Binomial
General Goals
Investigate the difference between the binomial distribution, which is a finite
discrete random variable, and the normal distribution, which is a continuous
random variable, and investigate using the appropriate normal distribution to
approximate the binomial using concrete explorations.
Instructional Objectives:
The student will learn to…
Calculate a binomial probability distribution table and then approximate
these probabilities with the appropriate normal distribution,
Identify the correct interval on the x-axis to use when using the normal
distribution to approximate the binomial, and
Know when to use the normal approximation of the binomial.
Prerequisite Learning:
The student should already
be able to…
Calculating the mean, standard deviation, probabilities, and probability
histograms of a binomial distribution.
Calculating normal distribution probabilities
Understanding the normal bell-shaped curve
Required Materials
Worksheet, graphing calculator
Length of Activity
30 minutes
Prerequisite/Required
Videos
While it is not absolutely required to watch the Normal Curve Approximation
Video ahead of time, it is highly suggested.
Warm Up
Binomial Probability Video, Normal Probability Video
Common Questions
Part II - Q: When do we add/subtract 0.5? A: When you are asked to use the
appropriate normal distribution to approximate the binomial distribution (or
when your calculator cannot handle the binomial probability).
Related/Optional Videos
Normal Curve Approximation Video
Calculator Videos
Binomial Probabilities and Normal Probabilities
Homework Assignment
Any text or online homework on the normal approximation of the binomial
Other Resources
Textbook and note sections on the
[If it exists, Don’s applet on this topic.]
Notes
Students need to have a good understanding of the finite discrete binomial
random variable and of the continuous normal random variable to get the most
out of this activity.