4-1. Exercises

1. BASIC

Ex 1. Classify each random variable as either discrete or continuous.

1. The number of arrivals at an emergency room between midnight and 6:00 a.m.

2. The weight of a box of cereal labeled “18 ounces.”

3. The duration of the next outgoing telephone call from a business office.

4. The number of kernels of popcorn in a 1-pound container.

5. The number of applicants for a job.

Ex 2. Classify each random variable as either discrete or continuous.

1. The time between customers entering a checkout lane at a retail store.

2. The weight of refuse on a truck arriving at a landfill.

3. The number of passengers in a passenger vehicle on a highway at rush hour.

4. The number of clerical errors on a medical chart.

5. The number of accident-free days in one month at a factory.

Ex 3. Classify each random variable as either discrete or continuous.

1. The number of boys in a randomly selected three-child family.

2. The temperature of a cup of coffee served at a restaurant.

3. The number of no-shows for every 100 reservations made with a commercial airline.

4. The number of vehicles owned by a randomly selected household.

5. The average amount spent on electricity each July by a randomly selected household in a certain state.

Ex 4. Classify each random variable as either discrete or continuous.

1. The number of patrons arriving at a restaurant between 5:00 p.m. and 6:00 p.m.

2. The number of new cases of influenza in a particular county in a coming month.

3. The air pressure of a tire on an automobile.

4. The amount of rain recorded at an airport one day.

5. The number of students who actually register for classes at a university next semester.

Ex 5. Identify the set of possible values for each random variable. (Make a reasonable estimate based on experience, where necessary.)

1. The number of heads in two tosses of a coin.

2. The average weight of newborn babies born in a particular county one month.

3. The amount of liquid in a 12-ounce can of soft drink.

4. The number of games in the next World Series (best of up to seven games).

5. The number of coins that match when three coins are tossed at once.

Ex 6. Identify the set of possible values for each random variable. (Make a reasonable estimate based on experience, where necessary.)

1. The number of hearts in a five-card hand drawn from a deck of 52 cards that contains 13 hearts in all.

2. The number of pitches made by a starting pitcher in a major league baseball game.

3. The number of breakdowns of city buses in a large city in one week.

4. The distance a rental car rented on a daily rate is driven each day.

5. The amount of rainfall at an airport next month.