Explore BrainMass


Queuing Gamma Distribution

At a certain bank, the amount of time that a customer spends being served bya teller is an exponential random variable with mean 5 minutes. If there is a customer in service when you enter the bank, what is the probability that he or she will still be with the teller after an additional 4 minutes?

Credit card usage

Each time that Ed charges his credit card, he omits the cents and records only the dollar value. If this month he has charged his credit card 20 times what can be said about the probability that the record shows at least $15 less than the actual amount?


Suppose that the demand for a company's product in weeks 1, 2, and 3 are each normally distributed and the mean demand during each of these three weeks is 50, 45, and 65, respectively. Suppose the standard deviation of the demand during each of these three weeks is known to be 10, 5, and 15, respectively. It turns out that if we

Statistics: test mean reaction time of female candidates for flight school

In a standard test for reaction time, female candidates for flight school are found to have times that are normally distributed with a mean of 0.65 seconds and a standard deviation of 0.15 seconds. If one candidate is randomly selected, find the probability that her reaction time is below the maximum allowable time of 1.00se

Statistics of statistics class

Of the students who have registered for a statistics class, 20% are business majors, 30% are finance majors, and the remainder are economics majors. 60% of the business majors are graduate students, 40% of finance majors are graduate students, and 30% of the economics majors are graduate students. (a) (4 points)What percentag

Probability Of Different Courses Being Ordered

1. Pizza House offers 4 different salads, 5 different kinds of pizza, and 4 different desserts. How many different three course meals can be ordered? 2. Assume the probability is ½ that a child born is a girl. If a family has three children, what is the probability that they have: a. Exactly one girl b. At most tw

Discrete Probability Distributions

The amount of a brand of soda in 12-ounces can is approx. normal with a mean of 12.1 ounces and a standard deviation of 0.15 ounces. (A) What is the probability that a randomly chosen can contains more than 12.3 ounces? Less than 11.9 ounces? (B) What percentage of the soda can contains less than the advertised 12 ounces?

Discrete Probability Distributions- Normal probability

The one-mile running time for CMS male athletes is approx. distributed normally with a mean of 7.5 minutes and a standard deviation of 0.6 mins. (A) What percentage of athletes run a mile in less than 7 minutes? In less than 8 mins? In more than 6.5? Between 7 and 8 mins? (B) If a male athlete is randomly chosen, what is the

Statistics and Successful Surgical Techniques

A surgical technique is performed on eight patients. You are told there is an 80% chance of success. a. Graph the binomial distribution using a relative frequency histogram b. Find the mean and standard deviation of the distribution c. What is the probability that the procedure is successful for exactly (2n)/2 patients if the

Normal Distribution of SAT Verbal Scores

SAT Verbal Scores are normally distributed with a mean of 430 and standard deviation of 120, fined the following: a. If one of the students is randomly selected, find the probability that student's Score is more than (440 + n) b. If 100 students are randomly selected, find the probability that their mean score is more than (44

Probability of Defective Computer Chips

The Binary Computer Company manufactures computer chips used in DVD players. Those chips are made with a (27 + n)% yield meaning that (27 + n)% of them are good and others are defective. a. If one chip is randomly selected, find the probability that it is not good. b. If two chips are randomly selected, find the probability th

Statistics: Poisson distribution

In the example: P(x; &#956;) = (e-&#956;) (&#956;x) / x! P(3; 2) = (2.71828-2) (23) / 3! P(3; 2) = (0.13534) (8) / 6 P(3; 2) = 0.180 Where 3! = 6, how was that number calculated? In the example: P(x < 3, 5) = P(0; 5) + P(1; 5) + P(2; 5) + P(3; 5) P(x < 3, 5) = [ (e-5)(50) / 0! ] + [ (e-5)(51) / 1! ] + [ (e-5)(52) /

Binomial Probability: Unfair Coin Flip

11) Suppose an unfair coin comes up tails 42% of the time if it is flipped. If the coin is flipped 13 times, what is the probability that? a) it comes up tails exactly 5 times. b) it comes up tails less than 4 times.

Normal Probability: Weights of Pumpkins

See the data file attached. John's Colorado farm grows some of the finest pumpkins around. Assume weights of pumpkins follow the normal probability distribution with a population weight of 16.0 lbs with a standard deviation of 3.65 lbs. Use Appendix D (posted with statistical tables in the course materials forum) or standard

Statistic Problems and Descriptive Question

I managed to do all my other questions but I cannot figure these specific problems out. They are not fully explained in the book and I cannot figure it out by searching for help online. I have worked all day yesterday and most of today on this and just cannot get these specific problems! If you could explain how to do them with

ANOVA and Regression Calculations

Case Study of ZYX Incorporated Case Study of ZYX Incorporated Executive Summary The below details is a summary of the research and findings that was completed by Team B Enterprises. This study was conducted with the employees to determine the job satisfaction and stress level of the recently announced move to a new locat


I NEED THEM BACK WITHIN 1 HR FROM NOW.SEE DATAS CAREFULLY. 1.According to Investment Digest (&quot;Diversification and the Risk/Reward Relationship&quot;, Winter 1994, 1-3), the mean of the annual return for common stocks from 1926 to 1992 was 15.4%, and the standard deviation of the annual return was 24.5%; During the same

Quantitative Analysis for Management (10th ed.)

From historical data, Harry's Car Wash estimates that dirty cars arrive at the rate of 10 per hour all day Saturday. With a crew working the wash line, Harry figures that cars can be cleaned at the rate of one every 5 minutes. One car at a time is cleaned in this example of a single-channel waiting line. Assuming Poisson arriva

Probability Distribution Represented

Determine whether each of the distributions given below represents a probability distribution. Justify your answer. (A) x 1 2 3 4 ______________________________ P(x) 1/12 5/12 1/3 1/12 (B) x 3 6 8 __________________________ P(x) 2/10 0.5 1/5

Bivariate density function: Computation of Moments

Random variables x and y have the joint density function fxy(x,y)={ (a(2x+y)^2)/20 -1 < x < 1 -3 < y < 3} { 0 elsewhere } a)find the value of the constant a b)find all the second order moments of X and Y c)what are variances of X and Y d)what is the correlation coefficient

Normal Probability: Life span of bulbs & Cut off mark..

1). In an examination the mean score was 80, the standard deviation was 10, and the grades followed a normal distribution. The instructor wants to assign A's to the top 12%. Where should the cutoff point for A's be? (2). A company manufactures electric light bulbs that have an average life of 1000 hours and a standard deviati

Poisson Probability: Major Hurricanes

1) A major hurricane is a hurricane with wind speeds of 111 miles per hour or greater. During the 20th century, the mean number of major hurricanes to strike the U.S. mainland per year was about 0.7. Find the probability that in a given year a) exactly one major hurricane will strike the U.S. mainland, b) at most one major hurr