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Variance

Business math homework problems

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

Show that constants are normally distributed.

Let X1 and X2 denoted independent, normally distributed random variables, not necessarily the same mean or variance. Show that any constants "a" and "b", Y= aX1 + bX2 is normally distributed. Help: ===== I'm not sure if I can just prove it by showing what I have below. where, SX2 ---> INTEGRATION FROM X_2 SX1 ---> INTEG

Order Statistics and Variance

From Order Statistics. Please show each step of your solution. You can use technological device(e.g. excel, Maple, or Mathematica, etc) if you want, but please explain your work.

Expected Values - Barron Big Money Poll

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

PMF, Variance and Skewness

From Mean, Variance, and Standard Deviation Please see the attached file for the fully formatted problem.

Uncertainty Exercises and Sums of Variances

Need just the answers. Basically, in the question where there is a question mark (?) should be replaced by the solution. Error of input quantities are assumed to be statistically independent Please see the attached file (with bilingual instruction).

Statistics

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

Stock Returns

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

Forecasting, Seasonal Variations, Cost Control

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

Error Sum of Squares

If the total sum of squares in a one-way analysis of variance is 25 and the treatment sum of squares is 17, then the error sum of squares is?

Crede Manufacturing: Price and quantity variances

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

MVB or UMVUE for Gamma

For the X~ Gamma (alpha, Lambda), Find the optimal estimators of n/lambda and n/lambda^2 Ether UMVUE or MVB may be used to find the estimator. See attached file for full problem description.

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

Statistics Questions

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

Relationship of a list of two variables

Suppose a small group of physicists and mathematicians, each an expert in his or her field... Relationship of a list of two variables. See attached file for full problem description.

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

Whole Number Variance

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

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

Moment around a Constant

(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) .

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

In a certain animal species...

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.

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

F-stat calculation for upholstery business

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