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Probability & Chance

An investment broker at your brokerage house tells you that he has found a mutual fund that has beaten the S&P market index in 16 of the past 25 weeks. Has he really found a winner or could this be due to chance? What is the probability that this result is due to chance? (By "due to chance," we mean that there is a 50-50 chan

Proportion and Percentage

The monthly spending on food of a family of three in Puerto Rico for the year 2000 is estimated in an average of $420.00/month with a standard deviation of $80.00. Assuming that the monthly spending in food is distributed normally (when presenting the processes, you need to include the corresponding graphs.): a) What proportion


1.) The probability of your doctor being late for the appointment is .4 and the probability the HMO will pay for your prescription is .7 and these events are independent of each other. a) Use the letters D and H to describe the "plain" events. D=" H=" b) Write correct probability statements for the following probabilit

Operation Management - Solver Model

Here is the scenario: You have four people sitting in jail. One has committed a terrible crime. They have made the following statements: Anita says: "Kitty did it." Kitty says: "Robin did it." Ed says: "I didn't do it." Robin says: "Kitty lied." Your favorite snitch tells you that only one person is telling the

Statistical Problems

1.) Listed below is the percent increase in sales for the MG Corporation over the last 5 years. Determine the geometric mean percent increase in sales over the period. (See attached) 2.) In 1996 a total of 14,968,000 taxpayers in the United States filed their individual tax returns electronically. By the year 2002 the numbe

A. What is the probability that a subscriber rented a car for personal or business reasons? b. What is the probability that a subscriber rented did not rent a car for either personal or business reasons?

A survey of magazine subscribers showed that 55.8% rented a car during the last 12 months for business reasons, 44% rented a car for personal reasons, and 25% rented a car for both business and personal reasons. a. What is the probability that a subscriber rented a car for personal or business reasons? b. What is the probab


1. Describe exactly what information is provided by a Z-score 2. A distribution has a standard deviation of Ï?=4. Find the z-score for each of the following locations in the distribution. a. Above the mean by 4 points b. Above the mean by 12 points c. Above the mean by 2 points d. Above the mean by 8 points 3. A distr

Operational Management Problems

These problems are Waiting Line Models. (1,2,3) The problems I need work out are: Problem 14, 19, and 20. See attached file for full problem description.

Four statistics and probability questions

10. The following examples are experiments and their associated random variables. In each case identify the values the random variable can assume and state whether the random variable is discrete or continuous. a. Take a 20-question exam Number of questions answered correctly b. Observe cars arriving at a tollbooth f

6 probability and statistics questions

CH3 Problem 50 The mean income of a group of sample observations is $500; the standard deviation is $40. According to Chebyshev's theorem, at least what percent of the incomes will lie between $400 and $600? CH3 Problem 62 The Citizens Banking Company is studying the number of times the ATM located in a Loblaws Supermarket

Waiting Line Model, Poisson Distribution, Exponential Distribution

A crew of mechanics at the San Jose Transportation Department garage repair vehicles that break down at an average of ë= 7.5 vehicles per day (Poisson Distribution). The crew under the supervision of the VTA city manager can service an average of ì= 10 vehicles per day with a repair time distribution that approximates an expo

Sampling and Business Research

Can type of sampling (probability, non-probability sampling) also affect the results of business research? Explain your answer.

The solution to Normal approximation to the binomial

A summer resort boast that 85% of its new visitors return the next five years. Use the normal approximation to the binomial to find the probability that, of 250 new visitors this summer, at least 200 will return some time within the next five years.

Probability Questions

Chapter 4, page 159, exercise 25 A local bank reports that 80 percent of its customers maintain a checking account, 60 percent have a savings account, and 50 percent have both. If a customer is chosen at random, what is the probability the customer has either a checking or a savings account? What is the probability the customer

Expected value from probability generating function.

1. The probability generating function for a Poisson random variable is where λ is a rate parameter and t is the index. Use this fact to show that the expected value of a Poisson random variable is λt.


A poll of 1,250 investors conducted, assume that 50% of the investors found the market less attractive to the prior years. P=.5, find the probability that the sample proportion obtained from the sample of 1,250 investors would be: A. within 4% points of the population, that is P(.46<^p<.54). B. within 2% points of the pop

Calculation of probability and Chebychev inequality

Please help with the following problem regarding probability. Provide calculations and explanations. 1. The probability of contracting the kissing disease is .23 when one is exposed to a certain provocative environment. Sixty people are so exposed. What is the probability that no more than 10 are infected with this dreaded d

Normal Probability/ Testing Hypothesis

The listed sample distances (in millimeters) were obtained by using a pupilometer to measure the distances between the pupils of adults (based on data collected by a student of the author) 67 66 59 62 63 66 66 55 ~ a) Find the mean x of the distances in this sample. b) Find the median of the distances in this samp

Interpreting Marginal Effects after the Probit Model

Interpreting Marginal Effects after the Probit Model: I have ran a Probit regression, then computed the Marginal Effects after Probit. I want to interpret the effects of men, education, and experience on the model. How does one make quantitative interpretations for this scenario? The output is below: Marginal effect

Statistics Problems based on Chebyshev Inequality

1. In an exam, the mean score is 70 and the variance is 16. What is the probability that a student's score will lie within the "54 to 86" range? (Hint: Use Chebyshev's inequality, as we saw in class). What percentage of students will lie within 2 standard deviations on either side of the mean score? 2. You are the CEO of a

Probability and Statistics question

Each salesperson at stiles compton is rated either below average, average, or above average with respect to sales ability. Each salesperson is also rated with respect to his or her potential for advancement: either fair, good or excellent. These traits for the 500 sales people were cross classified into the following table.

Poisson Distribution

True or false: Suppose that the number of airplanes arriving at an airport per minute is a Poisson process. The average number of airplanes arriving per minute is 3. The probability that exactly 6 planes arrive in the next minute is 0.0504.

Calculating Probability in a Normally Distributed Sample

The number of column inches of classified advertisements appearing on Mondays in a certain daily newspaper is normally distributed with a population mean of 320 and a population standard deviation of 20 inches. 1. Referring to the table above, for a randomly chosen Monday, what is the probability there will be less than 340

Example of Sample Space in an Random Experiment


Binomial Distribution and NC Army National Guard

In the military everything works of numbers. Recruiting is a good example of a binomial distribution. I'll use NC Army National Guard for an example. The NCARNG must have a set number of enlistments every year and they get the requirement for the year during October. This year the number is: 2000 (so n = 2000), the 2 out