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Normal Distribution

Determine the probability the sample mean

The mean television viewing time for Americans is 15 hours per week (Money, November 2003). Suppose a sample of 60 Americans is taken to further investigate viewing habits. Assume the population standard deviation for weekly viewing time is 4 hours. a. Determine the probability the sample mean will be within 1 hour of the pop

Random numbers

A normal distribution has a mean of 500 and a standard deviation of 50. A manager wants to simulate 2 values from this distribution, and has drawn these random numbers: -0.6 and 1.4. What are the 2 values respectively?

Expectation of normal distribution

I know this problem is very easy, finding E(x) from the distribution function. I tried to do it by integration by parts, one way I took x to be my first function and the whole exp term to be my 2nd function, but it didn't work, then I split the exponential term to 2 terms combined one with x as my first function and took the sec

Probability: Sample Proportions and Surveys

Approximately 5% of U.S. families have a net worth in excess of $1 million and thus can be called millionaires. However, a survey in the year 2000 found that 30% of Microsoft's 31,000 employees were millionaires. If random samples of 100 Microsoft employees had taken that year, what's the probability that the sample proportion

Random Selection and Normal Distribution

The diameter of a Ping-Pong ball manufactured at a factory is expected to be approximately normally distributed with a mean of 1.30 inches and a standard deviation of 0.04 inch. What is the probability that a randomly selected Ping-Pong ball will have a diameter between 1.31 and 1.33 inches? A. 0.0987 B. 0.1747 C. 0.2734

Independent random variables

(See attached file for full problem description) --- 4. Consider independent random variables, Xi, where Let Y = (a) Determine fY (y). Describe this distribution. Hint: This is probably easiest using moment generating functions.

Descriptive Statistics and Faulty Computers

A computer laboratory in a school has 33 computers. Each of the 33 computers has a 90% reliability. Allowing for 10% of the computers to be down, an instructor specifies an enrollment ceiling of 30 for his class. Assume that a class of 30 students is taken into the lab. a. What is the probability that each of the 30 students

Normal Distribution and Sigma Calculations

Assume that the life in hours of a radio tube is normally distributed with mean 100 hours. If a purchaser requires at least 90 percent of them to have lives exceeding 80 hours, please show that the largest value that sigma can have and still have the purchaser satisfied is 15.6.

Primary Financial Statements

1. Can you please provide a description of the 3 primary financial statements (balance sheet, income statement, and statement of cash flows) and what each statement tells users about an organization 2. Explain the components of each statement (assets, liabilities, equity, revenues, expenses) 3. Explain the set of activiti

Questions on CREDIT SCORES

Whenever you apply for credit someone will check your credit score. Here is some data obtained from one of the agencies that administers the credit score. The following is a distribution of FICO scores across the country: a. Over 800-11% of the population b. 700-800 - 49% of the population c. 600-700 - 27% of the pop

Various probability problems

Please find attached problem. (a) A five-gear assembly is put together with spacers between the gears. The mean thickness of the gears is 5.030 cm with a standard deviation of 0.008cm. The mean thickness of the spacers is 0.140 cm with the standard deviation of 0.005 cm. Find the mean and standard deviation of the assembled u

Bell curve problems

How do you develop a bell curve for 1,000 cases: With a given mean of 20 and a standard deviation of 2, how do you compute the -3,-2,-1 (mean), +1,+2,+3 points along the baseline of the curve (assuming the curve is normal)? Then repeat the mean of 10 pounds and the standard deviation is 4.5. Repeat again with a mean of 4 secon

Critical Value and Probabilities

4. (1) Assume that the readings on the thermometers are normally distributed with a mean of 0o and standard deviation of 1.00o C. A thermometer is randomly selected and tested. Draw a diagram and find the probability in degrees. Between -1.18 and 2.15 (2) The lengths of pregnancies are normally distributed with a mean of 2

Simulation using Crystal Ball / OptQuest

This problem requires the use "Crystal Ball", the popular commercial spreadsheet add-in. For clarity, it is distributed by Decisioneering, Inc. This problem specifically requires that Excel and "Crystal Ball" (and OptQuest as applicable) be used - and not any other software choices. The link below directs you to a free 7-day t

Random variable

Let x1 and x2 be independent normal random variables, x1 n(ui,oi2), and let y1 = x1 and y2 = x1+x2

ESP and Statistics

I need some help answering this question without calculus: In 1973, Charles Tart ran an experiment at UC Davis to test for ESP abilities. Tart used an electronic random number generators called the Aquarius with four "targets". The machine randomly picked one of the fours targets, and the subject guessed which target the machi

Moment of Inertia: Parallel axis theorem

(See attached file for full problem description with equations) (Steiner's theorem) If IA is the moment of inertia of a mass distribution of total mass M with respect to an axis A through the center of gravity, show that its moment of inertia IB with respect to an axis B, which is parallel to A and has the distance k from it,

Normal distribution

The resistances of carbon resistors of 1500 ohm nominal value are normally distributed with µ = 1500 and standard deviation = 200. a. What proportion of resistors is expected to have resistance greater than 1150 ohm? b. Within plus and minus what amount around the mean do 80 percent of resistances fall?

Verifying the Assumption of a Normal Distribution

How do you verify that the assumption of a normal distribution is correct if you have only the mean and standard deviation? What could you do if you actually have the data? In my case, the sample size is 1000; mean 40, and SD 10. If you then took a sample of 20 from the original sample of 1000, is the expected value 40? How

Probability and Samples

I have a random sample of n = 16 scores with a normal distribution, mean of 50 and standard deviation of 10. I need to calculate what range of values has a 95% probability of containing the sample mean. Here is where I get stuck. I have been provided the answer and it is 45.13 to 54.87 (50 +/- 4.87). I don't know how to

Trail Making Test and Noise pollution questions.

(See attached file for full problem description) --- 1. The Trail Making Test (TMT) is frequently used in neuropsychological assessment to provide a quick estimate of brain damage in humans. To investigate the neuropsychological deficits in alcoholics, 50 problem drinkers (25 drinkers under the age of 40 and 25 drinkers 40 y

Normal Distribution: Mean Labor Cost to Repair a Heat Pump

A recent article in the Cincinnati Enquirer reported that the mean labor cost to repair a heat pump is $90 with a standard deviation of $22. Monte's Plumbing and Heating Service completed repairs on two heat pumps this morning. The labor cost for the first was $75 and it was $100 for the second. Compute z values for each and com

Lee County Georgia Weekly Wages Sampling Distribution

In Lee County Georgia the distribution of weekly wages for workers in the construction industry is skewed to the right with mean equal to $473 (Georgia Department of Labor, Labor Market Information, 1999). Assume the standard deviation of the distribution is $25. An economist plans to randomly sample 40 workers in Lee County and

Linear Model Problem

(See attached file for full problem description) --- Let , i=1, 2, ...,m be a simple regression, where xi unobservable and assumed to be independent and identically distributed with common distribution Instead, we assume that, for each xi, zi1, zi2, . . . , zin are observed. Given xi, the conditional distribution for th

Standard distribution, deviation, etc.

15. If P(A) = 0.4, P(B| A) = 0.35, P(A  B) =0.69, then P(B) = a. 0.14 b. 0.43 c. 0.75 d. 0.59 18. If X and Y are mutually exclusive events with P(X) = 0.295, P(Y) = 0.32, then P(XY) = a. 0.0944 b. 0.6150 c. 1.0000 d. 0.0000 27. For a standard normal distribution, the probability of z  0 is