Random Variables and Probability Distributions
This section first defines discrete and continuous random variables. Then, it introduces the distributions for discrete random variables. It also talks about the mean and variance calculations.
BASIC
1. Classify each random variable as either discrete or continuous.
a. The number of arrivals at an emergency room between midnight and 6:00 a.m.
b. The weight of a box of cereal labeled "18 ounces".
c. The duration of the next outgoing telephone call from a business office.
d. The number of kernels of popcorn in a 1-pound container.
e. The number of applicants for a job.
3. Classify each random variable as either discrete or continuous.
a. The number of boys in a randomly selected three-child family.
b. The temperature of a cup of coffee served at a restaurant.
c. The number of no-shows for every 100 reservations made with a commercial airline.
d. The number of vehicles owned by a randomly selected household.
e. The average amount spent on electricity each July by a randomly selected household in a certain state.
5. Identify the set of possible values for each random variable. (Make a reasonable estimate based on experience, where necessary.)
a. The number of heads in two tosses of a coin.
b. The average weight of newborn babies born in a particular county one month.
c. The amount of liquid in a 12-ounce can of soft drink.
d. The number of games in the next World Series (best of up to seven games).
e. The number of coins that match when three coins are tossed at once.