Binomial Review
n! =
n
 
 x
Binomial Example
Suppose that a quiz has 6 questions. Each question has 5 possible answers. Suppose that each question
can be considered independent of each other. Suppose that Joe has not studied and is just guessing the
answers, so that the chance that he gets any question correct is 20%. Let X equal the number of
questions that he will get correct.
This is a Binomial Distribution. Check the conditions.
What is the expected number of questions that he will get correct?
What is the standard deviation?
What is the probability that he gets 2 questions correct by guessing?
What is the probability that he will get 4 questions correct by guessing?