Explore BrainMass

Explore BrainMass

    Variance

    BrainMass Solutions Available for Instant Download

    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

    Statistical Analysis of Psychotherapy Patients

    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

    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

    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

    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

    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.

    Functions : Cauchy Density Function and Joint Distribution

    4.17. X has the U(?pi/2, pi/2) distribution, and Y = tan(X). Show that V has density l/(pi(1 + y2)) for ?oo <y <oo . (This is the Cauchy density function.) What can be said about the mean and variance of Y? How could you simulate values from this distribution, given a supply of U(O, 1) values? 4.21. Let X and Y have joint den

    Proof of an unbiased estimator

    7.1.1 Show that the mean of a random sample of size n from a distribution having pdf f( x; &#952;) = (1/&#952;) e^-(x/&#952;), 0 <x < infinity, 0 < &#952; < infinity, 0 elsewhere, is an unbiased estimator of &#952; and has variance &#952;^2/n.

    Random Variables : Expected Values

    Let X be a random variable having expected value (mu) and variance (sigma)^2. Find the expected value and variance of: Y = (X - mu)/(sigma). (See attachment for full question)

    Density Function : Calculate the Expected Values

    1. Suppose U is a uniformly distributed random variable, so it has density fU(u) = 1 for 0&#61603;u&#61603;1, fU(u) otherwise. Calculate the expected values E[U] and E[U 2], and the variance of U. (Please see attachment.)

    Measuring convergence

    I need to measure the convergence of annual provincial data relative to the national. I have data for per capita annual income for two provinces and I have to compare them with the per capita national data and evaluate if the provincial data converge toward the national data. Can I do this with variance or standard deviation?

    Standard Deviation of Possible Sales Prices: Example Problem

    A firm has decided to invest in a piece of real estate. Management has estimated that the real estate can be sold in 5 years for the following possible prices: Price Possibility $20,000 .20 $25,000 .25 $30,000 .30 $35,000 .25 What is the standard deviation of possible sales prices? (

    Error variance is high

    Suppose the error variance in your study is high. Which of these statements is most likely to be true? a. Your power is high. b. The relationship between your independent variable and dependent variance is strong. c. Confounds interfered with measuring your dependent variable or manipulating your independent variable.

    Linear Model / Parabola / Exponential

    A. Which of the models would you use to determine the best choice of expiration date for the green beans? The cream pie? Why would you choose these? b. If, for practical reasons, you had to choose only one model to use to set the expiration dates, which would it be? (There is no health risk involved. It's a flavor quality thing