Exam 5: Discrete Probability Distributions

Which of the following statements is true with respect to a Poisson distribution?

Explain what the expected value of a discrete random variable measures.

Under what conditions is the binomial distribution symmetric?

A small city has 2 ambulances.Emergency calls for ambulances arrive randomly with an average of 0.2 calls per hour.They are concerned about the possibility of both ambulances being busy when an additional call comes in.What is the probability of more than 2 calls in a 1-hour period? Determine the correct distribution,explain why it is the best distribution to use,and find the probability.

Assuming that potholes occur randomly along roads,the number of potholes per mile of road could best be described by the:

Consider the following two probability distributions: Which of the following is an accurate statement regarding these two distributions?

If the number of defective items selected at random from a parts inventory is considered to follow a binomial distribution with n = 50 and p = 0.10,the expected number of defective parts is:

The hypergeometric probability distribution is used rather than the binomial or the Poisson when:

Each week American Stores receives a shipment from a supplier.The contract specifies that the maximum allowable percent defective is 5 percent.When the shipment arrives,a sample of 20 parts is randomly selected.If 2 or more of the sampled parts are defective,the shipment is rejected and returned to the supplier.Assume that a shipment arrives that actually has 4 percent defective parts and the distribution of defective parts is described by a binomial distribution.The probability that the shipment is accepted is approximately 0.81

The Nationwide Motel Company has determined that 70 percent of all calls for motel reservations request nonsmoking rooms.Recently,the customer service manager for the company randomly selected 25 calls.Assuming that the distribution of calls requesting nonsmoking rooms is described by a binomial distribution,the standard deviation of requests for nonsmoking rooms is 5.25 customers.

If cars arrive to a service center randomly and independently at a rate of 5 per hour on average,what is the probability of 0 cars arriving in a given hour?

A random variable is generated when a variable's value is determined by using classical probability.

A company has 20 cars that are available for use by company executives for official business purposes.Six of these cars are SUVs,8 are luxury type cars,and the rest are basic sedans.Suppose the cars are randomly assigned each week.If 5 cars are put into use,the chance that none of the SUVs or luxury cars will be in the group is approximately .0004.

A pizza restaurant uses 7 different toppings on its pizzas.At lunch time it has a pizza buffet and make pizzas with 2 toppings.If it wants to serve every possible combination of 2 toppings,it would need to make 14 different pizzas.

Six managers at a company all enjoy golf.Each Saturday,four of the six get together for 18 holes of golf.They have decided to set up a schedule so that the same foursome does not play twice before all possible foursomes have played.The number of weekends that will pass before the same group would play twice is 15.

If a distribution is considered to be Poisson with a mean equal to 11,the most frequently occurring value for the random variable will be:

When using the binomial distribution,the maximum possible number of success is the number of trials.

Which of the following statements is true?

A warehouse contains 5 parts made by the Stafford Company and 8 parts made by the Wilson Company.If an employee selects 3 of the parts from the warehouse at random,the probability that none of the 3 parts is from the Wilson Company is approximately .03496.

The number of calls to an Internet service provider during the hour between 6:00 and 7:00 p.m.is described by a Poisson distribution with mean equal to 15.Given this information,the standard deviation for the call distribution is about 3.87 calls.