Reference no: EM131043755
Instructions:
1) Complete the exam yourself. You may not work with anyone on an exam.
2) Show your work. For calculator problems, record the command(s) you used. Show all parts of each hypothesis test!!!!!!!
3) Do your calculations using formulas unless otherwise indicated.
4) You may assume that all samples are simple random samples.
1. What shape did I draw at the bottom of your graded Assignment 7?
2. What requirements (besides having a simple random sample) must be met to use the z-distribution to test a claim about a proportion?
3. What requirements (besides having a simple random sample) must be met to use the z-distribution to test a claim about a mean?
4. You are studying the mean cost of a emergency room visit. How many visits should you include in your sample to be 95% confident that your sample mean is within $250 of the population mean? Assume that the population standard deviation is known to be $790.
5. You are studying the proportion of emergency room bills that are not paid. How many bills should be in your sample to be 99% confident that your results are within .02 of the actual proportion?
6. The daily number of calls received at a call center is normally distributed. In a sample of 26 days, there was a mean of 521.5 calls with a standard deviation of 51.7 calls.
a. Create a 95% confidence interval estimate for the standard deviation in daily number of calls at the call center. Use formulas and chart.
b. Create a 95% confidence interval estimate for the mean daily number of calls at the call center. Use formulas and chart.
c. If the population standard deviation is known to be 68.6 calls, find a 95% confidence interval estimate for the mean daily number of calls at the call center. Use your calculator, and interpret your results ("We are...).
6. The daily number of calls received at a call center is normally distributed. In a sample of 26 days, there was a mean of 521.5 calls with a standard deviation of 51.7 calls. (Continued.)
d. With .01 significance, test the claim that the standard deviation in daily number of calls is 80. Use the critical value method.
e. With .05 significance, test the claim that the mean daily number of calls is greater than 500. Use the P-value method.
7. In a sample of 42 employers in a city, 64% offered vacation to employees during their first year.
a. Create a 90% confidence interval estimate for the proportion of employers who offer vacation to first-year employees. Use formulas and chart.
b. With .10 significance, test the claim that 55% of employers offer vacation to first-year employees.
Use your calculator.
|
What is the probability you will roll a double
: You roll two fair dice. What is the probability you will roll a double (two 1's, two 2's, two 03's, and so on)? (round to two decimal places)
|
|
Suppose sales associate told you the policy costs
: The Maybe Pay Life Insurance Co. is trying to sell you an investment policy that will pay you and your heirs $26,000 per year forever. Suppose a sales associate told you the policy costs $471,000. At what interest rate would this be a fair deal?
|
|
Paying dividends-what is the current share price
: Estes Park Corp. pays a constant $9.20 dividend on its stock. The company will maintain this dividend for the next 8 years and will then cease paying dividends forever. If the required return on this stock is 12 percent, what is the current share pri..
|
|
What is the maximum number of machines
: It costs a company $12 to purchase an hour of labor and $15 to purchase an hour of capital. If L hours of labor and K units of capital are available, then L23K13 machines can be produced. Suppose the company has $10,000 to purchase labor and capit..
|
|
How many visits should you include in your sample
: You are studying the mean cost of a emergency room visit. How many visits should you include in your sample to be 95% confident that your sample mean is within $250 of the population mean? Assume that the population standard deviation is known to..
|
|
What is the probability that both songs are country songs
: The disc jockey randomly chooses the first song to play, and then she randomly chooses the second song from the remaining ones. What is the probability that both songs are country songs? Write your answer as a fraction in simplest form.
|
|
.net framework basically constitutes which of the following
: .net framework basically constitutes of which of the following?
|
|
Fraction in simplest form
: A small class has 9 students, 6 of whom are girls and 3 of whom are boys. The teacher is going to choose two of the students at random. What is the probability that the first student chosen will be a girl and the second will be a boy? Write you..
|
|
Suppose in the spot market-dollar exchange rate
: Suppose in the spot market 1 U.S. dollar equals 1.75 Canadian dollars. 6-month Canadian securities have an annualized return of 6% (and thus a 6-month periodic return of 3%). 6-month U.S. securities have an annualized return of 6.5% and a periodic re..
|