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Expected Value. z-scores and other statistics concepts

1. For a sample selected from a population with a mean of µ=50 and a standard deviation of σ = 10: a. What is the expected value of M and the standard error of M for a sample of n=4 scores? b. What is the expected value of M and the standard error of M for a sample of n = 25 scores? 2. A population has a mean of µ

Reorder Point/ Optimal Order/ Total Carrying Cost

The manager of a car wash receives pricing schedule (shown below) from the vendor who supplies soap- and a promise of a 25% shorter lead time for deliveries. Currently, lead time is 4 days. Annual usage of soap is 4500 gallons. The car wash is open 360 days a year. Ordering Costs is $ 30 per order and annual holding costs are $

Joint Probability Distributions

Determine the value of c that makes the function f(x,y) = c(x+y) a joint probability density function over the range: x greater than 0 and less than 3 and x less than y less than x+2 a) P(X<1, Y<2) b) P(1<X<2) c) P(Y>1) d) P(X<2, Y<2) e) E(X) f) V(X) g) Marginal probability distribution of X h) Conditional probabilit

Probability Distribution for Audits

Question 1. An audit conducted by the St. Aleanis Hospital has determined that 15% of all patient bills contain an error of one form or another. After spending considerable effort to improve the hospital's billing process, the administrators are convinced that things have improved. They believe that the new error rate is somewhe

Random Variable/Uniform Distribution

A random variable Y is uniformly distributed over a range of 0 to 2*pi. Another random variable X is related to Y by X=cos(Y). Find the probability density function of X.


Problem 2. A recent study of the hourly wages of maintenance crew members for major airlines showed that the mean hourly salary was $20.50, with a standard deviation of $3.50. If we select a crew member at random, what is the probability the crew member earns: a. Between $20.50 and $24.00 per hour? b. More than $24.00 per hour?

Probability: Boat Schedules and Weather

1. During summer weekdays, boats arrive at the inlet drawbridge according to the Poisson distribution at a rate of 3 per hour. In a 2 hour period, what is the probability that 2 boats arrive? Please provide the answer in the form 0.xxxx or .xxxx. 2. A researcher wants to simulate sunny and rainy days in her town for a 3

M&M Statistics

I have been working with M&M's throughout this classes course. From the data I gathered I developed histograms and calculated descriptive statistics. Based on this data I then can make judgments on what I can expect to see when I buy packages of M&M's at the store. To do this I calculate what is called confidence limits

Probability Distribution of Hummingbirds Eggs Incubation Time

10. Wildlife Hummingbirds Selasphorus sasin is the scientific name for what is commonly called "Allen Hummingbird" This beautiful hummingbird lives on the west coast of the United States and is named C.A. Allen (1841-1930) , who studied these birds extensively. Let x be a random variable that represents the incubation time for

Simple Probability of Survey Results

Please help with the following problems. 3. Use this table to answer questions #3 through #5. Some students were asked if they carry a credit card. Here are the responses. Class______ | Credit Card Carrier | Not a Credit Card Carrier | Total Freshman______________33_______________________27________________60 Sophomore____

Probability Distribution - Mean and Standard Deviation

1. On average, 40% of U.S. beer drinkers order light beer. (5 points) a. What is the probability that none of the next eight customers who order beer will order light beer? b. What is the probability that one customer will? c. What is the probability that two customers will? d. What is the probability that fewer than three w

Mean, Median and other statistics questions

1. Some normal probability distributions may have the same mean, but their standard deviation may be different True or False 2. As the sample size increases, the standard error of the sample mean increases. True or False 3. Which of the following statement(s) about the normal probability distribution is/are true?

Calculating Probabilities without Standard Deviation

I need some guidance in how to calculate probabilities without knowing the std deviation. Population = 3005 calculate P(x-bar > 50.8) for sample size of n = 253 calculate P(x-bar > 50.6) for sample size of n = 134 calculate P(x-bar > 51) for sample size of n = 119 Then combine the two probabilities 51 a

Two Probability Questions.

1. A financial analyst estimates that the probability that the economy will experience a recession in the next 12 months is 20%. She also believes that if the economy enters a recession, the probability that her mutual fund will increase in value is 20%. If there is no recession the probability that the mutual fund will increase

Sample size, Sampling distribution of proportions

25) Money magazine reported that the average price of gallon of gasoline in the United States during the first quarter of 2001 was $ 1.46. Assume the price reported by Money is the population mean, and the population standard deviation is $ 0.15. a) What is the probability that the mean price for a sample of 30 gas sta

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 &#963; = 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

Business Math 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