What is the relationship between the variance and the standard deviation? Why is the unbiased estimator of variance used?
Homework #8 Question 1 refers to the finite random variable X, whose p.m.f. is given below. x 0 1 2 4 8 fX(x) 0.1 0.2 0.4 0.2 0.1 Compute the mean, X, variance, V(X), and standard deviation, , of X. Questions 6 and 7 refer to the random variable X which gives the number of customers who visit my busi
The Barron Big Money Poll asked 131 investment managers across the United States about their short-term investment outlook (Barrons, October 28, 2002). Their responses showed 4% were very bullish, 39% were bullish, 29% were neutral, 21% were bearish, and 7% were very bearish. Let x be the random variable reflecting the level of
1. The following sample observations were randomly selected. Determine the coefficient of correlation and the coefficient of determination. Interpret. 2. The following sample observations were randomly selected. Determine the coefficient of correlation and the coefficient of determination. Interpret the association betwee
A stock's return has the following distribution: Demand for the Company's Products Probability of This Demand Occurring Rate of Return if This Demand Occurs Weak 0.05 (40%) Below average 0.25 (4%) Average 0.40 20% Above average 0.25 35% Strong 0.05 55% 1.00 What is the stock's expected return? What is the stoc
1. The healthcare environment would be advised to use the MAD, MSE, and the MAPE as measures of forecasting accuracy. Describe how these techniques could aid managers in the projections of cost and assist in inventory control. 2. Summarize the factors involved with seasonal variations. Provide examples. 3. An essentia
A Stock's return has the following distribution: Demand for the company's products: Probability of this rate of return if it demand occurring occurs Weak 0.1
Crede Manufacturing uses standard cost accounting. In 2005, 33000 units were produced. Each unit took several pounds of direct materials and 1 1/3 standard hours of direct labor at a standart hourly rate of $12.00. Normal capacity was 42,000 direct labor hours. During the year 132,000 pounds of raw materials were purchased a
12.8 The following table lists possible rates of return on Compton Technology's stock and debt and on the market portfolio. The probability of each state is also listed. State Probability Return on Stock (%) Return on Debt (%) Return on the Market (%) 1 0.1 3% 8% 5% 2 0.3 8 8 10 3 0.4 20 10 15 4 0.2 15 10 20 1. What i
Distinguish between unpooled variance and pooled variance. What are the assumptions of each? How do you determine which is appropriate?
Derive the quantization formula based upon the variance of a sinewave and the variance of distortion due to quantization. This is the signal to distortion (SDR) ratio for a quantized sinewave. A is the amplitude of the quantized sinewave and Delta is the quantization interval of the analog to digital converter, and the quant
Should Statistics Be a Required Course in College? Yes No Republican 10 26 Democrat 15 17 1. Cell 1,1 (Yes, Republican) Expected Value = 2. Cell 2,2 (No, Democrat) Expected Value = (You must calculate E for the other two cells) 3. What is the result of this analysis? 4. What is
The IRS is concerned with improving the accuracy of tax information given by its representatives over the telephone. Previous studies involved asking a set of 25 questions of a large number of IRS telephone representatives to determine the proportion of correct responses. Historically the average proportion of correct responses
Use whole numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 to make up a list of 6 numbers. Use as many of the numbers, as many times as you want. Show a list of six numbers with the largest variance, and a list of six numbers with the smallest variance.
The Variance Inflationary Factor (VIF) measures the A. correlation of the X variables with the Y variable B. contribution of each X variable with the Y variable after all other X variables are included in the model C. correlation of the X variables with each other. D. standard deviation of the slope
Q5: A group of poker players are profile in this month's magazine. The table below lists their name and average winnings per tournament. Consider this to be a population. Player Average Winnings Seattle Slim $27000 KC Kate $33000 Minnesota Mel $45000 Gotham City Graced $35000 The Player $60000 a) find the mean and sta
(See attached file for full problem description) A set of numbers x_i, i = 1,...n, has a sample mean X and a variance. I would be grateful for a proof that the second moment of the x_i around a constant c is (see attachment) .
The manufacturer of batteries used in small electric appliances wants to establish the average life of a battery. A random sample of 12 batteries yields a sample mean of 34.2 hours, and a sample standard deviation of 5.9 hours. Give a 95% confidence interval for the average life of a battery. Assume the underlying distribution
In a certain animal species, the probability that a healthy adult female will have no offspring in a given year is .21, while the Probabilities of 1,2,3, or 4 offspring are respectively, .18, .29, .17, and .15. If a random variable X is used to represent the number of offspring, find its mean, variance, and standard deviation.
The use of preservatives by food processors has become a controversial issue. Suppose two preservatives are extensively tested and determined safe for use in meats. A processor wants to compare the preservatives for their effects on retarding spoilage. Suppose 15 cuts of fresh meat are treated with preservative A and 15 are tr
An upholstery business is studying differences between two of its major outlet stores in the time it takes customers to receive furniture that was custom ordered. The following data shows a sample of delivery times for the most popular types of furniture: (see chart in attached file) Which of the following is the corr
Please see the attached file for the fully formatted problems. keywords: rv r.v. irv i.r.v.
You're conducting a study where participants are randomly assigned to two independent variables: number of sessions of psychotherapy (6 vs. 12) and use of antidepressants (using vs. not) on psychotherapy outcome. You would be pretty happy if you were checking assumptions for your ANOVA test and found this result. A. Levene
What is ANOVA and how is it used?
Overview River Beverages is a food and soft-drink company with worldwide operations. The company is organized into five regional divisions with each vice president reporting directly to the CEO, Cindy Wilkins. Each vice president has an R&D department, controller, and three divisions; carbonated drinks, juices and water, and f
An instructor asked 5 students how many hours they had studied for an exam. Here are the hours and the students grades Hours Grade 0 52 10 95 6 83 8 71 6 64 a. make a scatter diagram of the raw scores b. describe in words the general pattern of association c. figure the correlation coefficient d. explain
X and Y are random variables. What are the marginal pdfs of (x+y) (where 0<x<1 and 0<y<1)? What is the expectation, covariance, correlation and and covariance coefficient? What are the joint and marginal pdfs and cdfs? (ii) Also,differently - if Fx|y(x|y) is constant over the 0 to 1. What is Fy|x(y|x)? (is there enough
At the end of 2003, Al Second, vice president of Chicago Syndicate, Inc., stared out the window of his posh west side office in dismay. His expectations for a highly profitable year were dashed. The disappointing results appear below: Mr. Second realized that because sales were down, expenses should also fall, such that pr
Mean and Variance : Compute the Mean and Variance of a Uniform Continuous Random variable on the interval [a, b].
Compute the Mean and Variance of a Uniform Continuous Random variable on the interval [a, b].
I need some help with this statistics problem as well as some help understanding limiting distribution and the limiting extreme-value distribution: Consider a random sample of size n from a distribution with CDF (cumulative distribution function) F(x)=1-1/x if , and zero otherwise. a) Derive the CDF of the smallest order sta