Explore BrainMass
Share

Variance

Pooled vs Unpooled Variance

Distinguish between unpooled variance and pooled variance. What are the assumptions of each? How do you determine which is appropriate?

Derive the quantization formula of a sine wave.

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

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

Math - Interpreting Results of Statistics

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

Let Y be a random variable...

Let Y be a random variable with p.d.f. ce^-6s for s > 0. (a) Determine c. (b) What is the mean, variance, and squared coefficient of variation of Y where the squared coefficient of variation of Y is defined as Var[Y]/(E[Y]^2)? (c) Compute Pr{Y > 6}. (d) Compute Pr{Y > 8 | Y > 2}. (e) What is the point x* such that Pr{Y > x*} = 1

The Variance Inflationary Factor (VIF) measures the

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

To show that population mean is equal to mean of sample mean.

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

Test of Variance with Significance Level

Madison Associates is a marketing research firm that specializes in comparative shopping. Tyler is hired by General Motors to compare the selling price of the Pontiac Sunbird with the Chevy Cavalier. Posing as a potential customer, a representative of Madison visited 8 Pontiac dealerships in Sun city and 6 Chevrolet dealership

How Many Test Runs for a Sample Size?

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

Calculating the f-stat to determine the difference between preservatives

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

Adjusting to Level of Confidence and Sampling Error

When determining the sample size for a proportion for a given level of confidence and sampling error, the closer to 0.50 that p is estimated to be, the ___________ the sample size required. A. Smaller B. Larger C. Sample size is not affected D. The effect cannot be determined from the information given

Moment Generating Function Discussion

Thank you for your messages, indicating that there is a mistake in the question. Please find the moment generating function for x=1, 2, and then please solve the amended question: Given f(x)=(1/2)^x, for x=0,1,2,..., and zero elsewhere, please show that its moment generating function is M(z)=2(2-e^z)^-1. Please use it to calc

How "between" and "within" treatments are different

How are "between" and "within" Treatments Different?

ANOVA Introduction

What is ANOVA and how is it used?

Budget

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

Correlation

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

Random Variables and Statistical Analysis

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

Managerial Accounting : Material, Labor and Overhead Variances and their Relationship to Profit

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

Compute the Mean/Variance of Uniform Continuous Random Variables

Compute the Mean and Variance of a Uniform Continuous Random variable on the interval [a, b].

Limiting Extreme-Value Distribution

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

Expected Return and Risk and Portfolios

1) What has been the expected return and risk for the S&P 500 during that time period (average annual return and standard deviation)? 2) How does the portfolio fair compare to the S&P 500? Explain. 3) Your client has \$50,000 to invest and you plan to invest 60% in the security with the highest expected return. What would b

Finance Questions : Risk and Return, Rate of Return and Scenario Analysis

Risk and Return. True or false? Explain or qualify as necessary. a. The expected rate of return on an investment with a beta of 2 is twice as high as the expected rate of return of the market portfolio. b. The contribution of a stock to the risk of a diversified portfolio depends on the market risk

Random Sample and Uniform Random Variables

Let Y the sum of a random sample of n=192 uniform random variables on the interval (0,1). Use a normal approximation to find P(Y>100).

Finding the variance of a random variable, given its pdf

Find the variance of the random variable Y, where the pdf of Y is given by f(y) = 3(1 - y)^2, 0 < y < 1.

A Discussion On The Proportion Of Variance

Hours Studied...........Test Grade ........0..............................52 .......10.............................95 ........6..............................83 ........8..............................71 ........6..............................64 Give the proportion of variance accounted for (R2).

Standard Deviation, Variance, Mean, Median and Mode

Q1. For the set of numbers given: 9, 8, 7, 27, 16, 3, 1, 9, 4 and 16 determine: (a) the mean (b) the median (c) the mode (d) the variance from the mean and from it calculate the standard deviation. All calculations must be shown for (a), (b) and (c) and a hand drawn table consisting of manipulated data elements and calculati

Difference Between Standard Deviation and Variance

What is the difference between standard deviation and variance? Please provide an example of the relationship between the two.

Effect of the Independent Variable

If we do not observe a sufficiently large between-groups variance, then we have not observed __________ experimenter effects, an effect of the dependent variable, enough samples, or an effect of the independent variable I believe - enough samples - is the answer.

Variance: Gamma Random Variable

Verify that Var(X) = α/λ² when X is a gamma random variable with paramaters α and λ. See the attached file.