Explore BrainMass


Probability and mean / standard deviation at electronics firm

The personnel office at a large electronics firm regularly schedules job interviews and maintains records of the interviews. From the past records, they have found that the length of a first interview is normally distributed with mean = 35 minutes and standard deviation = 6 minutes. Nine first interviews are usually scheduled p

Probability in birth weight between babies

Consider babies born in the "normal" range of 37 - 43 weeks gestational age. Extensive data supports the assumption that for such babies born in the United States, birth weight is normally distributed with mean = 3432 grams and standard deviation = 482 grams. What is the probability that the birth weight of a randomly selecte


Let X be a normally distributed random variable with µ = 100 and σ = 10. The probability that X is between 70 and 110 is (to the nearest whole percent) a. 8 % b. 84 % c. 95% d. answer not listed


In a survey on the quality of customer service at Car Toys, customers were asked to rate the service on a scale from 1 to 10, with 10 being that a customer was completely satisfied. Assume that the distribution of the responses can be approximated by a normal distribution with a mean of 7 and a std deviation of 1. a. What is

Review Questions

See attached Review Questions (9, 10 and 15) #'s 9 & 10 refer to the following situation. Fifteen (15) companies all bid on oil leases. The following data is a small part of the records on past bids. All monetary amounts are in millions of dollars. Leases Signals Proven Value Company 1 Company 2 $105.5 $99.5 $107.4

Probability, Linear Programming

Please see attachment. 1. Roger's Regalia is a manufacturer of caps, gowns, and assorted party outfits, primarily for the commencement season. (80 percent of their yearly sales occur over a six-week period.) One of their popular products is a Parrot Head, sometimes worn by graduating college students as a sign of festive oc

Probability and Probability Distributions

1) In a certain town, 60% of adults have a college degree. The accompanying table describes the probability distribution for the number of adults (among 4 randomly selected adults)who have a college degree. Find the variance for the probability distribution. x P(x) 0 0.0256 1 0.1536 2 0.3456 3 0.3456 4 0.1296 2) A

You are trying to set up a portfolio that consists of a corporate bond fund and a common stock fund. Compute the covariance of the corporate bond fund and the common stock fund. Compute the portfolio expected return and portfolio risk for each of the following percentages invested in a corporate bond fund: a. 30% , b. 50%, c. 70%

You are trying to set up a portfolio that consists of a corporate bond fund and a common stock fund. the following information about the annual return (per $1,000)of each of these investments under different economic condition is available, along with probability that each of these economic conditions will occur: probability

weights of catfish are normally distributed

1. The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with mean of 3.2 pounds and standard deviation of 0.8 pound. What percentage of samples of 4 fish will have sample means between 3.0 and 4.0 pounds? a) 84% b) 67% c) 29% d) 16% 2. The standard error of t

Probability and normal distribution : key information

1. At a computer manufacturing company, the actual size of computer chips is normally distributed with a mean of 1 centimeter and a standard deviation of 0.1 centimeter. A random sample of 12 computer chips is taken. What is the standard error for the sample mean? a) 0.029 b) 0.050 c) 0.091 d) 0.120 2. The owner of a fish

Rule of 68-95-99.7

I have enrolled anywhere from 7 to 10 students for the past 6 months. Please put this as an example in the rule of 68-95-99.7 (please be specific) In addition, what is the probability of me enrolling more students?

Probability Distribution

Assuming A and B are independent events, if P(A) = 0.50 and P(A and B)= 0.21, then, P(B) = 2. Assume a production process is uniformly distributed between 8 and 12 minutes; the probability of the process taking between 9 and 12 minutes is :

A certain airplane has two independent alternators to provide electrical power.

Prepare answers to the following assignments from the e-text, Applied Statistics in Business and Economics, by Doane and Seward: Chapter 5 - Chapter Exercises 5.62 and 5.70 Note: Methods of computation could include the usage of Excel, SPSS, Lotus, SAS, MINITAB, or by hand computation. 5.62 A certain airplane has tw


There are two urn, a green urn and a red urn. The green urn contains 17 green balls and the red urn contains 15 red balls.Each round, one ball is chosen randomly from either urn. The probability that the green urn on any given round is chosen is 4/7. The probability that the red urn is chosen is 3/7. What is the probabil

Probability: fax costs

Please help me with the attached questions. Please also provide the formulas used and how the numbers are plugged into the formula. Thank you. 1.) Faced with rising fax costs, a firm issued a guideline that transmissions of 10 pages or more should be sent by 2-day mail instead. Exceptions are allowed, but they want the averag

Marginal and Joint Probability

1. A company markets two products (Product A and Product B) through mail order. The company will market them in sequence with the first mail order offer for product A. It feels that there is a 30% chance that any customer will purchase product A. Product B is offered some months later. It is felt, for product B, that there is

Mary and John toss a coin three times

Mary Tosses a coin 3 times and john does the same. A) Find probability Mary obtains one head. I have that answer which i think is 1/33 or 33%, but do I include John's tosses also in that? b) Find the probability that Mary obtains exactly one head and so does John. Here I thought to do 1/2 times 1/2 = 1/4 is that right?

Probability: Insurance, Population, Medicare and TV Viewing

1. National Association of Insurance Commissioners The average annual cost of automobile insurance is $687 (National Association of Insurance Commissioners, January 2003). Use this value as the population mean and assume that the population standard deviation is σ = $230. Consider a sample of 45 automobile insurance polic