Statistical Inference: A Short Course

Exercises

1. Which of the following random variables (X) is discrete? Why? [Hint: List the appropriate values for each X.]

a. X is the number of light bulbs on a chandelier containing eight light bulbs that need to be replaced this week.

b. X is the number of lobsters eaten at a picnic on the beach.

c. X is the number of customers frequenting a convenience store during business hours.

d. X is the number of points scored by the hometown football team.

e. X is the number of free-throw attempts before the first basket is made.

f. X is the number of senior citizens attending the next town council meeting.

2. Table E.5.2 contains data pertaining to the results of a survey in which n = 300 people were randomly selected and asked to indicate their preference regarding the candidates for the upcoming mayoral election. Transform this absolute frequency distribution to a discrete probability distribution. What key process allows us to do this?

Table E.5.2 Survey Results.

Candidate	Absolute Frequency
Mary Smith	100
William Jones	50
Charles Pierce	40
Harold Simms	110

3. Which of the following tables represents a legitimate discrete probability distribution? Why?

4. Given the following discrete probability distribution, find the following:

5. The accompanying table provides ...