Reference no: EM132402461
1. Suppose you are working with a data set that is normally distributed with a mean of 400 and a standard deviation of 20. Determine the value of x such that 60% of the values are greater than x. Show your work
2. Completion time (from start to finish) of a building remodeling project is normally distributed with a mean of 200 work-days and a standard deviation of 10 work-days. The probability that the project will be completed within 185 work-days is. Show your work.
3. Problem 8.6: A candy company fills a 20-ounce package of Halloween candy with individually wrapped pieces of candy. The number of pieces of candy per package varies because the package is sold by weight. The company wants to estimate the number of pieces per package. Inspectors randomly sample 81 packages of this candy and count the number of pieces in each package. They find that the sample mean number of pieces is 18.72. Assuming a population standard deviation of 0.87. Construct a 99% confidence interval to estimate the mean number of pieces per package for the population.
4. Problem 8.18: According to Runzheimer International, the average cost of a domestic trip for business travelers in the financial industry is $1,250. Suppose another travel industry research company takes a random sample of 49 business travelers in the financial industry and determines that the sample average cost of a domestic trip is $1,192, with a sample standard deviation of $280. Construct a 98% confidence interval for the population mean from these sample data. Now go back and examine the $1,250 figure published by Runzheimer International. Does it fall into the confidence interval computed from the sample data? What does this tell you? Show your work.
5. Problem 8.42: A bank officer wants to determine the amount of the average total monthly deposits per customer at the bank. He believes an estimate of this average amount using a confidence interval is sufficient. How large a sample should he take to be within $200 of the actual average with 99% confidence? He assumes the population standard deviation of total monthly deposits for all customers is about $1,000. Show your work