Explore BrainMass

# Probability

### Probability: school children with asthma

A research company stated that 20% of missed school days are due to asthma. If a group of 400 school children are selected at random, what is the probability that fewer than 70 will miss school because of asthma? a) 0.1056 b) 0.0947 c) 0.1170 d) 0.4049 e) None of the above

### Applied Probability: Example Problem

A research company stated that 20% of missed school days are due to asthma. If a group of 400 school children are selected at random, what is the probability that fewer than 70 will miss school because of asthma? a) 0.1056 b) 0.0947 c) 0.1170 d) 0.4049 e) None of the above

### 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 - Defectives, Cards

12) If 3% of the electric bulbs manufactured by a company are defective, find the probability that in a sample of 100 bulbs, five are defective 13) Three cards are drawn from a deck of 52 cards without replacement. Find the probability that a) two are jacks and one is king b) all cards are of one unit

### 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

Finding the number of different combinations.

### 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?

### Poisson Distribution, Confidence Interval, & Probability

1) If you buy a box of Wisk, the probability of getting a scoop is 97%. If you buy 9 boxes over the next several months, what is the probability of missing two scoops? 2) The average length of a cellular phone call in the U.S. is 3.4 minutes. If the standard deviation of those calls is .07 minutes (population standard deviati

### 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

### 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

### Statistics

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

### 9 short answer type questions on mean, standard deviation, range, probability, permutation

1. Compute the arithmetic mean for the following data: 8, 2.2, 25, 7, -9, 10, 2, and 5.9. 2. An Embry-Riddle senior performed the same experiment on three groups of subjects (with permission!) and obtained mean scores of 84, 69 and 76. The groups consisted of 13, 31, and 27 subjects respectively. What is the overall mea

### Standard Normal Distribution and Binomial Distribution

It is estimated that the probability that the general population will live past their 85th birthday is 5.4%. Use the standard normal distribution to approximate this Binomial problem and answer the following questions. Out of a sample of 600, what is the probability that fewer than 30 will live beyond their 85th birthday?

### Statistics

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

### Chips in Urn Probability

An urn contains 8 red chips, 10 green chips and 2 white chips. A chip is drawn and replaced and then a second chip is drawn. What is the probability of: A) a white chip on the first draw B) a white chip on the first draw and a red on the second C) two green chips being drawn D) a red chip on the second draw given a

### Calculating the binomial probability question using a normal standard distribution table.

Acme Plumbing Supply has just received a shipment of 5,000 valves for chemical plants, where regular steel valves would corrode. However, it is known that in the shipment 50 of the valves are regular steel which were inadvertently included. Unfortunately there was no was to distinguish between the two types of valves. They

### Probability

An urn contains 8 red chips, 10 green chips, and 2 white chips. A chip is drawn and replaced and then a second chip is drawn. What is the probability of? a.) A white chip on the first draw b.) A white chip on the first draw and a red on the second. c.) Two green chips being drawn. d.) A red chip on the second draw given a

### independent continuous random variables

1)If X and Y are both discrete, show that ʸ ̄ 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 using mean and standard deviation

The weights of medium oranges packaged by an orchard are normally distributed with a mean of 14 ounces and a standard deviation of 2 ounces. The weights of large oranges are normally distributed with a mean of 18 ounces and a standard deviation of 3 ounces. If we select, at random, one each of the medium and large oranges, deter

### Flaws Probability

The following data are the result of a historical study of the number of flaws found in a porcelain cup produced by a manufacturing firm. Use these data and the associated probabilities to compute the expected number and the standard deviation of flaws. Flaws Probability 0 0.461 1 0.285 2 0.129 3 0