Reference no: EM13916972
1. A random sample of 90 observations produced a mean 25.9 and a standard deviation 2.7. Find an approximate 95% confidence interval for the population mean.
2. A study conducted showed that a random sample of 15 of newborns on the average weighed 6.7 pounds with a standard deviation of 1.2 pounds. Assume the distribution of these weights is approximately normal. Find a 95% confidence interval for the population mean.
3. A city wants to estimate the mean number of gallons of water use per household per day. From experience, it is known that the standard deviation of such usage is 40 gallons. The city intends to collect a random sample and monitor the water usage.
(a) Suppose that they take a sample of size 196 with mean 300 gallons, find a 90% confidence interval for the population mean.
(b) Suppose the city needs to be within 5 gallons of the true value with a 95% confidence. How large a sample will be needed?
(c) Suppose they take a sample of size 150. With what level of certainty can they ensure that the error in their estimate of the mean usage is no more than 4.5?
4. A random sample of eight tax filers who completed the forms themselves found that they had 1, 3, 0, 4, 2, 3, 1, and 2 mistakes on their forms. Find a 90% confidence interval for the mean number of mistakes for tax filers that completed the forms themselves.
5. A random sample of size 225 yielded a sample proportion .46.
(a) Is the sample size large enough to construct a Large-Sample confidence interval for p? (b) Construct a 95% confidence interval for p.
6. Suppose you are trying to estimate the proportion of college students that live off campus their sophomore year. How large a sample will be needed to be 99% confident that our estimate will be off by no more than .05 if
(a) A similar study was done 5 years ago that indicated that 60% of sophomores live off campus? (b) No prior knowledge is known?
|
Critically important real economic variable
: (60 points total - 10 points each part) In this first homework assignment, we are getting our ‘hands dirty' to get familiar with some of the major macroeconomic variables that we will be using and working with throughout the semester. Our first c..
|
|
Prepare an outline that tells how to conduct the session
: Prepare an outline that tells how to (a) prepare for a brainstorming session, (b) conduct the session, and (c) follow up after the meeting. Submit your outline in a memo or an e-mail to your supervisor (your instructor).
|
|
Five steps of hypothesis testing
: List the five steps of hypothesis testing, and explain the procedure and logic of each.
|
|
Aging approach is used to estimate bad debts
: Refer to Atlantis Tropicals. If the aging approach is used to estimate bad debts, how much bad debts expense will the company report for 2012?
|
|
Find confidence interval for the population mean
: A random sample of 90 observations produced a mean 25.9 and a standard deviation 2.7. Find an approximate 95% confidence interval for the population mean
|
|
What three changes would you make to existing product lines
: If you were in charge of Gap or Old Navy's product lines, what three changes would you make to the existing product lines? What three totally new product lines would you want to create?
|
|
Simple web page updates
: A non-profit organization would like you to lead a Web site development proj¬ect for them. The organization has Internet access that includes space on a Web server, but has no experience developing Web pages or Web sites.
|
|
What is the minimum sample size required
: A fast food restaurant executive wishes to know how many fast food meals teenagers eat each week. What is the minimum sample size required to create the specified confidence interval
|
|
Allowance for uncollectible accounts
: A company has the following balances on December 31, 2015, before any year-end adjustments: Accounts Receivable = $82,000; Allowance for Uncollectible Accounts = $1,100 (credit)
|