need help with a 10 question worksheet from my QNT/275 class. Some questions have multiple parts and there is plenty of time to have it completed. Can you please help me?

qnt275r6_wk4_practice_set.docx

Unformatted Attachment Preview

Don't use plagiarized sources. Get Your Custom Essay on

statistics worksheet The critical z-value is calculated using Excel function

Just from $13/Page

Practice Set 4

QNT/275 Version 6

University of Phoenix Material

Practice Set 4

Practice Set 4

1. Find z for each of the following confidence levels. Round to two decimal places.

A. 90%

B. 95%

C. 96%

D. 97%

E. 98%

F. 99%

2. For a data set obtained from a random sample, n = 81 and x = 48.25. It is known

that s = 4.8.

A. What is the point estimate of µ? Round to two decimal places

B. Make a 95% confidence interval for µ. What is the lower limit? Round to two decimal

places.

C. Make a 95% confidence interval for µ. What is the upper limit? Round to two decimal

places.

D. What is the margin of error of estimate for part b? Round to two decimal places.

3. Determine the sample size (nfor the estimate of µ for the following.

A. E = 2.3, s = 15.40, confidence level = 99%. Round to the nearest whole number.

B. E = 4.1, s = 23.45, confidence level = 95%. Round to the nearest whole number.

C. E = 25.9, s = 122.25, confidence level = 90%. Round to the nearest whole number.

4. True or False.

a.The null hypothesis is a claim about a population parameter that is assumed to be false until

it is declared false.

A. True

B. False

b. An alternative hypothesis is a claim about a population parameter that will be true if the

null hypothesis is false.

A. True

B. False

c. The critical point(s) divide(s) is some of the area under a distribution curve into rejection

and nonrejection regions.

A. True

B. False

Copyright © 2017 by University of Phoenix. All rights reserved.

1

Practice Set 4

QNT/275 Version 6

d. The significance level, denoted by a, is the probability of making a Type II error, that is,

the probability of rejecting the null hypothesis when it is actually true.

A. True

B. False

e. The nonrejection region is the area to the right or left of the critical point where the null

hypothesis is not rejected.

A. True

B. False

5. A Type I error is committed when

A. A null hypothesis is not rejected when it is actually false

B. A null hypothesis is rejected when it is actually true

C. An alternative hypothesis is rejected when it is actually true

6. Consider H0: µ = 45 versus H1: µ < 45. A random sample of 25 observations produced a
sample mean of 41.8. Using a = .025 and the population is known to be normally distributed
with s = 6.
A. What is the value of z? Round to two decimal places.
B. Would you reject the null hypothesis?
1. Reject Ho
2. Do not reject Ho
7. The following information is obtained from two independent samples selected from two
normally distributed populations.
n1 = 18
x1 = 7.82
s1 = 2.35
n2 =15
x2 =5.99
s2 =3.17
A. What is the point estimate of µ1 - µ2? Round to two decimal places.
B. Construct a 99% confidence interval for µ1 - µ2. Find the margin of error for this estimate.
Round to two decimal places.
8. The following information is obtained from two independent samples selected from two
populations.
n1 =650
x1 =1.05
s1 =5.22
n2 =675
x2 =1.54
s2 =6.80
Test at a 5% significance level if µ1 is less than µ2.
a) Identify the appropriate distribution to use.
Copyright © 2017 by University of Phoenix. All rights reserved.
2
Practice Set 4
QNT/275 Version 6
A. t distribution
B. normal distribution
b) What is the conclusion about the hypothesis?
A. Reject Ho
B. Do not reject Ho
9. Using data from the U.S. Census Bureau and other sources, www.nerdwallet.com estimated
that considering only the households with credit card debts, the average credit card debt for U.S.

house- holds was $15,523 in 2014 and $15,242 in 2013. Suppose that these estimates were based

on random samples of 600 households with credit card debts in 2014 and 700 households with

credit card debts in 2013. Suppose that the sample standard deviations for these two samples

were $3870 and $3764, respectively. Assume that the standard deviations for the two populations

are unknown but equal.

a) Let µ1 and µ2 be the average credit card debts for all such households for the years 2014

and 2013, respectively. What is the point estimate of µ1 – µ2? Round to two decimal

places. Do not include the dollar sign.

b) Construct a 98% confidence interval for µ1 – µ2. Round to two decimal places. Do not

include the dollar sign.

1. What is the lower bound? Round to two decimal places.

2. What is the upper bound? Round to two decimal places.

c) Using a 1% significance level, can you conclude that the average credit card debt for such

households was higher in 2014 than in 2013? Use both the p-value and the critical-value

approaches to make this test.

A. Reject Ho

B. Do not reject Ho

10. Gamma Corporation is considering the installation of governors on cars driven by its sales

staff. These devices would limit the car speeds to a preset level, which is expected to improve

fuel economy. The company is planning to test several cars for fuel consumption without

governors for 1 week. Then governors would be installed in the same cars, and fuel

consumption will be monitored for another week. Gamma Corporation wants to estimate the

mean difference in fuel consumption with a margin of error of estimate of 2 mpg with a 90%

confidence level. Assume that the differences in fuel consumption are normally distributed

and that previous studies suggest that an estimate of sd=3sd=3 mpg is reasonable. How many

cars should be tested? (Note that the critical value of tt will depend on nn, so it will be

necessary to use trial and error.)

Copyright © 2017 by University of Phoenix. All rights reserved.

3

…

Purchase answer to see full

attachment

Basic features

- Free title page and bibliography
- Unlimited revisions
- Plagiarism-free guarantee
- Money-back guarantee
- 24/7 support

On-demand options

- Writer’s samples
- Part-by-part delivery
- Overnight delivery
- Copies of used sources
- Expert Proofreading

Paper format

- 275 words per page
- 12 pt Arial/Times New Roman
- Double line spacing
- Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Delivering a high-quality product at a reasonable price is not enough anymore.

That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

Read moreEach paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.

Read moreThanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.

Read moreYour email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.

Read moreBy sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.

Read more
The price is based on these factors:

Academic level

Number of pages

Urgency