Probability Workbook For Dummies

Chapter 8

Juggling Success and Failure with the Binomial Distribution

IN THIS CHAPTER

Identifying a binomial distribution

Finding probabilities for the binomial distribution

Calculating the mean and variance of the binomial distribution

The binomial distribution is used when the data fall into one of two groups: yes (success) and no (failure). The idea is to count the number of yeses that result from n “trials,” or n observations of a random phenomenon. Like flipping a coin, for example. You can get heads or tails. If you want to count the number of heads in ten flips, you call a head a “yes” or a “success” and a tail a “no” or a “failure.”

You can find probabilities of getting certain results, such as the probability of getting eight heads out of ten flips (which you’d guess is pretty small), or the probability of getting five heads out of ten flips (which has a higher chance of happening).

In this chapter, you first look at the characteristics of the binomial distribution and find probabilities for it, and then practice calculating the mean, variance, and standard deviation of it.

Identifying the Characteristics of the Binomial Distribution

A binomial distribution has the following ...