Exam 6: Discrete Probability Distributions

The variance of a probability distribution is based on the sum or squared differences from the mean.

The production department has installed a new spray machine to paint automobile doors. As is common with most spray guns, unsightly blemishes often appear because of improper mixture or other problems. A worker counted the number of blemishes on each door. Most doors had no blemishes; a few had one; a very few had two; and so on. The average number was 0.5 per door. The distribution of blemishes followed the Poisson distribution. Out of 10,000 doors painted, about how many would have no blemishes?

There are eight flights from Minneapolis to St. Cloud each day. The probability that any one flight is late is 0.10. Using the binomial probability formula, what is the probability that exactly 1 flight is late?

The binomial probability distribution is always negatively skewed.

A machine shop has 100 drill presses and other machines in constant use. The probability that a machine will become inoperative during a given day is 0.002. During some days, no machines are inoperative, but during some days, one, two, three, or more are broken down. What is the probability that fewer than two machines will be inoperative during a particular day?

A _______________ random variable can assume only a certain number of separated values.

A statistics professor receives an average of five e-mail messages per day from students. Assume the number of messages approximates a Poisson distribution. What is the probability that on a randomly selected day she will have five messages?

The probability of a particular outcome must always be between 0.0 and 1.0 inclusive.

A company is studying the number of monthly absences among its 125 employees. The following probability distribution shows the likelihood that people were absent 0, 1, 2, 3, 4, or 5 days last month. What is the mode of the distribution?

A total of 60% of the customers of a fast food chain order a hamburger, French fries, and a drink. If a random sample of 15 cash register receipts is selected, what is the probability that 10 or more will show that the above three food items were ordered?

For a binomial distribution, the mean is 0.6 and n = 2. What is π for this distribution?

David's gasoline station offers 4 cents off per gallon if the customer pays in cash and does not use a credit card. Past evidence indicates that 40% of all customers pay in cash. During a one-hour period, 15 customers buy gasoline at this station. What is the probability that all 15 pay in cash?

There are 10 flights from Minneapolis to St. Cloud each day. The probability that any one flight is late is 0.05. Using the binomial probability formula, what is the probability that 1 or more are late?

The variance of a binomial distribution is found by nπ (1 - π).

Elly's Hotdog Emporium is famous for its chilidogs. Elly's latest sales indicate that 30% of the customers order their chilidogs with hot peppers. Suppose 15 customers are selected at random. What is the probability that all 15 will want hot peppers?

When observing a checkout line at a food store, the average number of people served is 15 per hour. Using the Poisson distribution, what is the probability that 10 people check out in any given hour?

The variance measures the skewness of a probability distribution.

A company is studying the number of monthly absences among its 125 employees. The following probability distribution shows the likelihood that people were absent 0, 1, 2, 3, 4, or 5 days last month. What is the variance of the number of days absent?

When observing a checkout line at a food store, the average number of people served is 30 per hour. Using the Poisson distribution, what is the standard deviation of the number of people served in an hour?

For the following probability distribution: The standard deviation is _____________.