Stats Help for College-level Students

Calculating the sample size given confidence levels and standard deviation.

A researcher is interested in estimating the average salary of police officers in a large city. She wants to be 95% confident that her estimate is correct. If the standard deviation is $1050, how large a sample is needed to get the desired information and to be accurate within $200?

Setting up constraints.

How do I set up the contraints? A firm is engaged in the production of three types of products A, B, and C. The products earn profit of $3, $5 and $4 per unit respectively. Each product goes through three operations: cutting, sewing, and inspection. During the next period, the firm has 300 hours of cutting, 300 hours of se ...continues

Setting up constraints for profit maximization.

A florist is planning to make up floral arrangements for the upcoming holiday weekend. He has following supply of flowers in stock this Friday and he cannot get any more. Type------Number available------Cost per flower Roses----------800-----------------------0.20 Carnations---4000----------------------0.15 Gardenias ...continues

Statistical Inference

SCENARIO: The U.S. Bureau of Labor Statistics (http://www.bls.gov) released hourly wage figures for western countries in 2000 in the manufacturing sector. The hourly wage was $24.01 in Germany, $22.00 in Japan, and $19.86 in the United States. PROBLEM: Suppose 40 manufacturing workers are selected randomly from across ...continues

Calculating the probability in a given situation using the probability distribution table.

The U.S. Bureau of Labor Statistics (http://www.bls.gov) released hourly wage figures for western countries in 2000 in the manufacturing sector. The hourly wage was $24.01 in Germany, $22.00 in Japan, and $19.86 in the United States. PROBLEM: Suppose 50 manufacturing workers are selected randomly from across the Un ...continues

Calculating confidence intervals.

SCENARIO: The U.S. Bureau of Labor Statistics (http://www.bls.gov) released hourly wage figures for western countries in 2000 in the manufacturing sector. The hourly wage was $24.01 in Germany, $22.00 in Japan, and $19.86 in the United States. Problem: Construct a 95% confidence intervals for the average hourly wag ...continues

Binomial Distribution

The manager of a restaurant claims that only 3% of the customers are dissatisfied with the service. If this claim is true, what is the probability that the number of dissatisfied customers, in a random sample of 25 customers will be a) 0 b) at least 1 c) between 1 and 5 inclusive d) greater than 5 e) 25

3 Probability Questions

Here are questions 33 and 34 to assist in answering question 52. 33) Let X be a random variable with probability density f(x)={c(1-x^2), -1 ...continues

Probability Questions

30)Let X be a Poisson random variable with parameter (lambda). Show that P {X=i} increases monotonically and then decreases monotonically as i increases, reaching its maximum when i is the largest integer not exceeding (lambda). Hint: Consider P{X=i}/P{X=i-1}. 37) Let X1, X2, ...., Xn be independent random variables, each ...continues

Conditional probability

4) In a survey conducted to determine cost of vacations, 164 individuals were randomly sampled. Each person was asked to assess the total cost of his or her most recent vacation. The average cost was $1,386. Assuming that the standard deviation was $400, find a 94% confidence interval for the average cost of all vacation trips. ...continues