Explore BrainMass



1.Find the probabilities for the standard normal random variable z: P(-1.55<z<.44) 2. Find zo such that P(-zo<z<zo)=.99 3. A normal random variable x has mean =1.20 and standard deviation =.15. Find the probability of the x value. 1.35<x<1.50 b. x>1.38 4. Assume the heights of men have a mean of 69 inches with a stan


26. MCQ: A family center conducted research on carbohydrate consumption in the high school and found that 30% of all high school sophomores ate at least four candy bars a day. If 20 high school sophomores are selected at random, what is the probability that exactly 6 of these eat at least 4 candy bars a day? a) 0.300 b)

Statistics: geological study and large elevator

1. A geological study indicates that wells drilled in a certain area should strike water with probability 0.2. Find the probability that: a) first strike of water comes in the 3rd well drilled b) 3 strikes of water in 5 drills 2. A large elevator has a max weight limit of 10,000 lbs. Suppose a load has 45 boxes. This has a

Probability using Binomial Distribution

7) On a very hot summer day, 5% of the production employees at Midland States Steelare absent from work. The production employees are to be selected at random for a special in-depth study on absenteeism.What is the probability of selecting 10 production employee at random on a hot summer day and finding that none of them are abs

Working with combinations.

I have 9 chalkboards to be distributed amongst 4 classrooms. If each class must get at least 1 chalkboard, how many possible divisions can I have?

Binomial Probability

A factory employs several thousand workers, of whom 30% are Hispanic. If the 15 members of the union executive committee were chosen from the workers at random, the number of Hispanics on the committee would have the binomial distribution with n=15 and p=0.3 a)What is the probability that exactly 3 members of the committee are

Working with binomial probability.

If the parents have 5 children, the number who have type O blood is a random variable X that has the binomial distribution with n=5 and p=0.25 a) What are the possible values of X? b) Find the probability of each value of X. Draw a histogram to display this distribution. (Because probabilities are long-run proportions, a hi

Statistics Problem

For a given data set Mean = u=200 and standard deviation =30. What is the probability that the mean of a sample of n=36 a) would be greater than 208? b) Less than 195? c) Between 192 and 210? d) Not more than 212?

A Decision Tree

Details: An electric power trading company has an option to buy 1,000,000 terawatts of electricity from a producer for $10 per terawatt. Other electric power trading companies have received this option and the company knows a decision must be made quickly. The company estimates it can sell the electricity for $14 per terawatt if

Statistics Multiple choice: The Exhibits are the sentences or tables of numbers below the Exhibit number. Total 15 multiple choice questions. In the following multiple-choice questions, circle the correct answer and give 1-3 line defense for your choice:

16. If a coin is tossed three times, the likelihood of obtaining three heads in a row is a. zero b. 0.500 c. 0.875 d. 0.125 e. None of the above answers is correct. 17. If A and B are independent events with P(A) = 0.05 and P(B) = 0.65, then P(A|B) = a. 0.05 b. 0.0325 c. 0.65 The following rep

Decision making with probabilities

Dollar Department Stores has received an offer from Harris Diamonds to purchase Dollar's store on Grove Street for $120,000. Dollar has determined probability estimates of the store's future profitability, based on economic outcomes, as: P($80,000) = .2, P($100,000) = .3, P($120,000) = .1, and P($140,000) = .4.

Simulation: a. Conduct a 10-day simulation of this business using Row #1 below for demand and Row #2 below for rental length. b. You find out that your firm can obtain another car for $200 for 10 days. Should you take the extra car?

As the owner of a rent-a-car agency you have determined the following statistics: Potential Rentals Daily Probability Rental Duration Probability 0 .10 1 day .50 1 .15 2 days .30 2 .20 3 days .15 3 .30 4 days .05 4 .25 The gross profit is $40 per car per day rented. When there is demand for a c


Find the probability and expected value.

Find the expected value, variance, standard deviation, and probability.

1) A $25,000 investment in a tract of land may be worth $10,000, $25,000, or $45,000 after one year, the probabilities of these values being 0.25, 0.45, and 0.3, respectively. a) What is the expected value of the investment in one year? b) If your expected return on the investment is the expected present value of the investm

Questions on probability distributions - Binomial, Poisson

1 The Kwik Klean Car Wash loses $30 on rainy days and gains $120 on days when it does not rain. If the probability of rain is 0.15, what is the expected value of net profit? 2. The Newman Construction Company bids on a job to construct a building. If the bid is won, there is a 0.7 probability of making a $175,000 profit and t


A tire company made a sampling distribution on one of its brands of tires and determined that the tire had a mean life of 56,000 miles with a standard deviation of 18,100 miles. a. What is the probability that the life of a single tire will be less than 50,000 miles? b. What is the probability that the mean life of a sampl

Immunity, IQ etc. Probability Questions

2. The probability that a person is immune to a certain disease is 0.40. a) What is the probability that 4 people will have the disease in a sample of 12 people b) Find the mean number of people who have immunity in a sample size of 12. c) Find the standard deviation for the same sample 3. If the capacities of the cran


1)If X and Y are both discrete, show that &#61669;xPX/Y9x/y)=1 for all y such that pY(y)>0. 10) Suppose X and Y are independent continuous random variables. Show that E[X/Y=y]=E[X] for all y

Coins question

52) (from pg. 52) A coin, having probabiliyt p of landing heads, is flipped until head apears for the rth time. Let N denote the number of flips required. a) Calculate E[X] for the maximum random variable fo Exercise 37. b) Calculate E[X] for X as in Exercise 33. c) Calculate E[X] for X as in Exercise 34.

Probability Questions

30)Let X be a Poisson random variable with parameter (lambda). Show that P {X=i} increases monotonically and then decreases monotonically as i increases, reaching its maximum when i is the largest integer not exceeding (lambda). Hint: Consider P{X=i}/P{X=i-1}. 37) Let X1, X2, ...., Xn be independent random variables, each

Binomial Distribution

The manager of a restaurant claims that only 3% of the customers are dissatisfied with the service. If this claim is true, what is the probability that the number of dissatisfied customers, in a random sample of 25 customers will be a) 0 b) at least 1 c) between 1 and 5 inclusive d) greater than 5 e) 25

Calculating the probability from a given situation using combinations.

A class is given a list of 20 study problems from which 10 will be part of an upcoming exam. If a given student knows how to solve 15 of the problems, find the probablility that the student will be able to answer, a. All 10 questions on the exam b. Exactly 8 questions on the exam c. At least 9 questions on the exam

Binomial Distribution

Merican air flight 2705 from N.Y. to San Francisco has seats for 340 passengers. An average of 7% of the people with reservations do not show up so American Air overbooks by accepting 355 reservations for the 340 seats. We can analyze this system by using a binomial distribution with N=355 and P=0.93 (the probability that a boo

Trials and probability

Steps: 2) Find p-hat(R), the proportion of days on which it rained given that it rained the pervious day. 3) Find p-hat (NR) the proportion of days on which it rained given that it did not rain the previous day. 4) Construct confidence intervals for both p-hat(R) and P-Hat(NR) (you can chose level of confidence)

Understanding and calculating probability distribution.

A researcher is studying IQ levels. From past experience she knows the population mean IQ for adults is 110 and the standard deviation is 15. a) If samples of 30 IQs are selected and the sample mean is calculated for each sample, what can be said about the sampling distribution of the sample means, and why? b) If she ta