User Account

All Pages

Construct the confidence interval for the population mean

Assignment Help Basic Statistics
Reference no: EM13871604

1. Find the critical value zc necessary to form a confidence interval at the level of confidence shown below.

c = 0.83

2. Use the values on the number line to find the sampling error.

2374_Find the critical value.png

3. Find the margin of error for the given values of c, s, and n.

c = 0.90, s = 3.4, n = 64

4.  Match the level of confidence, c = 0.98, with its representation on the number line, given x' = 59.1,
s = 8.9, and n = 55.

5. Construct the confidence interval for the population mean μ.

c = 0.95, x' = 15.6, s = 3.0, and n = 40

A 95% confidence interval for μis ( ).

6. Use the confidence interval to find the margin of error and the sample mean.

(0.374, 0.470)

7. People were polled on how many books they read the previous year. How many subjects are needed to estimate the number of books read the previous year within one book with 99% confidence? Initial survey results indicate that σ = 15.6 books.

8. Find the critical value tc for the confidence level c = 0.50 and sample size n = 17. t- Distribution table

Level of
confidence, c

0.50

0.80

0.90

0.95

0.98

0.99

One tail, a

0.25

0.10

0.05

0.025

0.01

0.005

d.f.                     Two tails, a

0.50

0.20

0.10

0.05

0.02

0.01

1

1.000

3.078

6.314

12.706

31.821

63.657

2

.816

1.886

2.920

4.303

6.965

9.925

3

.765

1.638

2.353

3.182

4.541

5.841

4

.741

1.533

2.132

2.776

3.747

4.604

5

.727

1.476

2.015

2.571

3.365

4.032

6

.718

1.440

1.943

2.447

3.143

3.707

7

.711

1.415

1.895

2.365

2.998

3.499

8

.706

1.397

1.860

2.306

2.896

3.355

9

.703

1.383

1.833

2.262

2.821

3.250

10

.700

1.372

1.812

2.228

2.764

3.169

11

.697

1.363

1.796

2.201

2.718

3.106

12

.695

1.356

1.782

2.179

2.681

3.055

13

.694

1.350

1.771

2.160

2.650

3.012

14

.692

1.345

1.761

2.145

2.624

2.977

15

.691

1.341

1.753

2.131

2.602

2.947

16 a

.690

1.337

1.746

2.120

2.583

2.921

17

.689

1.333

1.740

2.110

2.567

2.898

181a

.688

1.330

1.734

2.101

2.552

2.878

19

.688

1.328

1.729

2.093

2.539

2.861

20

.687

1.325

1.725

2.086

2.528

2.845

21

.686

1.323

1.721

2.080

2.518

2.831

22

.686

1.321

1.717

2.074

2.508

2.819

23

.685

1.319

1.714

2.069

2.500

2.807

214_-a

.685

1.318

1.711

2.064

2.492

2.797

25

.684

1.316

1.708

2.060

2.485

2.787

26

.684

1.315

1.706

2.056

2.479

2379

27

.684

1.314

1.703

2.052

2.473

2.771

28

.683

1.313

1.701

2.048

2.467

2.763

29

.683

1.311

1.699

2.045

2.462

2.756

co

.674

1.282

1.645

1.960

2.326

2.576

9. Construct the indicated confidence interval for the population mean μusing (a) a t-distribution. (b) If you had incorrectly used a normal distribution, which interval would be wider?

c = 0.99, x' = 12.2, s = 2.0, and n = 5

a. The 99% confidence interval using a t-distributionis.

b. If you had incorrectly used a normal distribution, which interval would be wider?

10. In a random sample of five microwave ovens, the mean repair cost was $70.00 and the standard deviation was $12.50. Assume the variable is normally distributed and use a t-distribution to construct a 90% confidence interval for the population mean μ.

What is the margin of error of μ?

11. The monthly incomes for 12 randomly selected people, each with a bachelor's degree in economics, are shown below.

Assume the population is normally distributed.

4450.36     4596.43     4366.26

4455.52     4151.31     4407.46

4283.11     4527.74     4407.46

3946.48     4023.48     4221.98

a. Find the sample mean.

b. Find the sample standard deviation.

c. Construct a 99% confidence interval for the population mean μ.

12. In a random sample of 75 bolts, the mean length was 1.77 inches and the standard deviation was 0.08 inch. Use a normal distribution or a t-distribution to construct a 90% confidence interval for the mean.

Which distribution should be used to construct the 90% confidence interval?

13. Let p be the population proportion for the following condition. Find the point estimates for p and q.

In a survey of 1641 adults from country A, 560 said that they were not confident that the food they eat in country A is safe.

14. A researcher wishes to estimate, with 95% confidence, the proportion of adults who have high-speed Internet access. Her estimate must be accurate within 2% of the true proportion.

a. Find the minimum sample size needed, using a prior study that found that 46% of the respondents said they have high-speed Internet access.

b. No preliminary estimate is available. Find the minimum sample size needed.

15. The table to the right shows the results of a survey in which 2564 adults from Country A, 1120 adults from Country B, and 1085 adults from Country C were asked if human activity contributes to global warming. Complete parts (a), (b), and (c).

Adults who say that human

activity contributes to global

warming

Country A

65%

Country B

86%

Country C

93%

a. Construct a 99% confidence interval for the proportion of adults from Country A who say human activity contributes to global warming.

b. Construct a 99% confidence interval for the proportion of adults from Country B who say human activity contributes to global warming.

c. Construct a 99% confidence interval for the proportion of adults from Country B who say human activity contributes to global warming.

16. Find the critical values χ2L and χ2R for the given confidence level c and sample size n.

c = 0.95, n = 26

17. You randomly select and measure the contents of 10 bottles of cough syrup. The results (in fluid ounces) are shown.

4.214     4.297     4.252     4.247     4.183

4.288     4.263     4.246     4.228     4.239

Assume the sample is taken from a normally distributed population. Construct 80% confidence intervals for

a. The population variance σ2.

b. The population standard deviation σ.

18. The monthly incomes of 13 randomly selected individuals who have recently graduated with a bachelor's degree in economics have a sample standard deviation of $349. Construct a confidence interval for the population variance σ2 and the population standard deviation σ. Use a 90% level of confidence. Assume the sample is from a normally distributed population.

19.   The number of hours of reserve capacity of 10 randomly selected automotive batteries is shown.

1.79     1.86     1.53     1.63     1.78

1.98     1.39     1.53     1.41     2.02

Assume the sample is taken from a normally distributed population.Construct 90% confidence interval for

a. The population variance σ2.

b. The population standard deviation σ.

Reference no: EM13871604

Questions Cloud

What is the length of the string : 1. A thin stick one metre long is suspended at one end from the ceiling by a string.  As it swings, the angle of the stick to the vertical is consistently twice that of the string.  What is the length of the string? (Show all working.)
Prepare a retainer agreement for a client : Draft and prepare a retainer agreement for a client according to the following facts, Describe the sort of matter you are representing the client on and any limits on that representation
What actions can a multinational corporation take : What actions can a multinational corporation take that would make globalization a positive development for the global economy?
Calculations to prove that the selling price of the bonds : Prepare calculations to prove that the selling price of the bonds is $285,880.07.
Construct the confidence interval for the population mean : Construct the confidence interval for the population mean - estimate the number of books read the previous year within one book with 99% confidence
Current fair price of the bond with the given term structure : C. Estimate the 2-year, 5-year, and10-year key rate durations of a 20-year bond carrying a coupon of 12.3 percent on face value $100 paid semi-annually. The given term structure starts with 7.6 percent spot rate of interest at time zero and rises at ..
Describe the elements of leadership influence : Describe the elements of leadership influence
Calculate the npv of investing in a single mine : Calculate the NPV of investing in all five mines as a now-or-never alternative. Calculate the NPV (as of t = 0) of investing in a single mine and then waiting one year before considering investment in the other four mines.
Has benes acted properly under rules of professional conduct : After talking to Kramer, Benes decides, in fairness to both parties, to "split the difference." She writes up the agreement and presents it to both parties to sign. Has Benes acted properly under the rules of professional conduct? Discuss

Reviews

Write a Review

Basic Statistics Questions & Answers

  Megan concludes that she should not have any more problems

question suppose a friend named megan indicates that she has had a string of bad luck. within the past month she has

  Assume that bobs golf scores g approximately follow a

assume that bobs golf scores g approximately follow a normal distribution with a mean of 77and standard deviation of

  Number of tumors in a fish living in a river

Let X be the number of tumors in a fish living in a river. Suppose that it has the following probability mass function f(0) = 0.9 f(1) = 0.7 f(2) = 0.02 f(3) = 0.01 A random sample of size n = 30 is selected from this population. Approximate the p..

  For the same question a random sample of 400 kumon students

kumon promotes a method of studying mathematics that it claims develops mathematical ability. do data support this

  Probability of drawing cards

We have a deck of 52 playing cards. What is the probability of drawing?

  What are the null and alternative hypotheses what is the

a non profit company concerned with the school dropout rates in a nearby state has designed a tutoring program aimed at

  What does the multiple standard error of estimate measure

what does the multiple standard error of estimate measure? select one a. change in 1for a change in x1 b. the error or

  A telemarketer makes 80 calls in a one day with a 10 random

if you upload an image please make sure it is clear and your writing is legible.a telemarketer makes 80 calls in a one

  A person has 8 friends but can only invite 5 to their

a person has 8 friends but can only invite 5 to their birthday party. how many ways can she invite 5 friends if two of

  Using 10 pairs of sample data if you compute the value of

using 10 pairs of sample data if you compute the value of the linear correlation coefficient r and obtain a result of

  Calculate the sample variance and sample standard deviation

the following data are the temperatures of effluent at discharge from asewage treatment facility on consecutive days43

  Computing mean and variance

What is the expected value and variance for the number of contacts in eight attempts?

Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

Submit Assignment

Academics

Major Subjects

Majors

Get In Touch

whatsapp: +1-415-670-9521

Phone: +1-415-670-9521

Email: [email protected]

TERMS & POLICIES

HELP & SUPPORT

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd