In a large university, a study was conducted to estimate the mean annual expenditure of its students on textbooks. The expenditure of a student may be regarded as a random variable that is normally distributed witha population standard deviation $250. Suppose a random sample of 50 students is drawn and the sample mean is calculated to be $1,000.(a) What is a 95% confidence interval estimate for the population mean?Answer: [Select](b) Later, it was discovered that there were 65 students whose data had been collected but the researcher omitted the data of 15 of the students by mistake and reported the sample size was 50. Let K denote a 95%confidence interval for the population mean based on the data from all the 65 students. Let L be the 95% confidence interval obtained in part (a). What can we conclude about K and L?Answer: [Select](c) The data for the 15 students who were omitted in part (b) has an average value of $830. Using the information of all the 65 students, what is a 95% confidence interval estimate for the population mean?Answer: [Select]

Let random variable X be the expenditure of students and is normally distributed.x¯ = 1000 is the…

Answered: In a large university, a study was…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

Three experiments investigating the relation between need for cognitive closure and persuasion were performed. Part of the study involved administering a "need for closure scale" to a group of students enrolled in an introductory psychology course. The "need for closure scale" has scores ranging from 101 to 201. For the 65 students in the highest quartile of the distribution, the mean score was x = 175.10. Assume a population standard deviation of ? = 7.55. These students were all classified as high on their need for closure. Assume that the 65 students represent a random sample of all students who are classified as high on their need for closure. How large a sample is needed if we wish to be 99% confident that the sample mean score is within 1.5 points of the population mean score for students who are high on the need for closure? (Round your answer up to the nearest whole number.)students
(a) A study is interested in the proportion of postgraduate students who have met the criteria of depression during their study periods. In a random sample of 50 postgraduate students, 15 are found to be afflicted. Use the normal distribution table to construct a 98% confidence interval for the proportion of postgraduate students who have experienced depression. What can we assert with 98% confidence about the possible size of our error if we estimate the proportion to be 0.30?
(5) A statistician of a small criminal justice program wanted to estimate the average number of books required by instructors. Using bookstore data, he drew a random sample of 30 courses and obtained a sample mean of 1.8 books and a sample standard deviation of (0.4). Construct a 99% confidence interval to estimate the mean number of books assigned by instructors on campus.
Three experiments investigating the relation between need for cognitive closure and persuasion were performed. Part of the study involved administering a "need for closure scale" to a group of students enrolled in an introductory psychology course. The "need for closure scale" has scores ranging from 101 to 201. For the 75 students in the highest quartile of the distribution, the mean score was x = 176.90. Assume a population standard deviation of ? = 7.71. These students were all classified as high on their need for closure. Assume that the 75 students represent a random sample of all students who are classified as high on their need for closure. Find a 95% confidence interval for the population mean score ? on the "need for closure scale" for all students with a high need for closure. (Round your answers to two decimal places.)
Three experiments investigating the relation between need for cognitive closure and persuasion were performed. Part of the study involved administering a "need for closure scale" to a group of students enrolled in an introductory psychology course. The "need for closure scale" has scores ranging from 101 to 201. For the 70 students in the highest quartile of the distribution, the mean score was x = 176.30. Assume a population standard deviation of σ = 7.71. These students were all classified as high on their need for closure. Assume that the 70 students represent a random sample of all students who are classified as high on their need for closure. How large a sample is needed if we wish to be 99% confident that the sample mean score is within 1.7 points of the population mean score for students who are high on the need for closure? (Round your answer up to the nearest whole number.)
: A sample of 8 earnings per share estimates for 1998 is shown below: AT&T 2.92 Caterpillar 4.65 Eastman Kodak 4.27 Exxon 3.09 Hewlett-Packard 3.57 IBM 7.04 McDonald’s 2.64 Wal-Mart 1.74 Compute the sample variance and sample standard deviation for these data? 2. What is the 95% confidence interval for the population variance? 3. What is the 95% confidence interval for the population standard deviation?
What Proportion of Americans Say They Are Poor? A survey of 1000 US Adults conducted in October 2019 found that 182 of them described themselves as poor. In Exercise 3.128, we used a bootstrap distribution to find a 90% confidence interval for the proportion of all US adults who would describe themselves as poor. Here, we find this 90% confidence interval using the normal distribution and a formula for the standard error, as follows: (a) Give value for the sample statistic.Value = . (b) Find the standard error for this sample statistic. Round to three decimal places. (c) What is z* for a 90% confidence interval? Round to three decimal places. (d) Use the results of (a), (b), and (c) to find the 90% confidence interval. Round to three decimal places. to
1. (a) Eight randomly selected batches of a chemical were tested for impurity concentration. The percentage impurity levels found in the sample were as follows: 5.3 6.2 4.1 5.4 3.6 5.6 4.8 (b) (c) (d) 4.2 (0) (ii) Calculate the sample mean and sample variance. Construct a 95% confidence interval for the population mean. A random sample of 35 new graduates from Bangor University shows a mean starting salary of £17,250 and a standard deviation of £3,088. Construct a 95% confidence interval for the population mean starting salary. A components manufacturer claims that its average proportion of defective components is 1%. 65 defectives were found in a particular batch of 5000 components. Using the sample data, construct a 95% confidence interval for the population proportion of defectives. Provide a recommendation as to whether or not the company's claim should be believed. A loan auditor at a bank wishes to consider the loan balance for all customers who are currently carrying overdrafts.…
Three experiments investigating the relation between need for cognitive closure and persuasion were performed. Part of the study involved administering a "need for closure scale" to a group of students enrolled in an introductory psychology course. The "need for closure scale" has scores ranging from 101 to 201. For the 65 students in the highest quartile of the distribution, the mean score was x = 178.50. Assume a population standard deviation of σ = 8.41. These students were all classified as high on their need for closure. Assume that the 65 students represent a random sample of all students who are classified as high on their need for closure. Find a 95% confidence interval for the population mean score μ on the "need for closure scale" for all students with a high need for closure. (Round your answers to two decimal places.) lower limit upper limit
Question 2: On a particular day, Mobay electronics produced 1000 electric bulbs at a mean production rate of 10 hours. Assume that the known population standard deviation is 2000 hours a. Why do we need a confidence interval? b. Construct a 95% confidence interval for the mean production time of the light bulbs of mobay electronics.
Three experiments investigating the relation between need for cognitive closure and persuasion were performed. Part of the study involved administering a "need for closure scale" to a group of students enrolled in an introductory psychology course. The "need for closure scale" has scores ranging from 101 to 201. For the 84 students in the highest quartile of the distribution, the mean score was x = 176.70. Assume a population standard deviation of σ = 8.39. These students were all classified as high on their need for closure. Assume that the 84 students represent a random sample of all students who are classified as high on their need for closure. How large a sample is needed if we wish to be 99% confident that the sample mean score is within 1.6 points of the population mean score for students who are high on the need for closure? (Round your answer up to the nearest whole number.) USE SALT students

Recommended textbooks for you

MATLAB: An Introduction with Applications

Statistics

ISBN:

9781119256830

Author:

Amos Gilat

Publisher:

John Wiley & Sons Inc

Probability and Statistics for Engineering and th…

Statistics

ISBN:

9781305251809

Author:

Jay L. Devore

Publisher:

Cengage Learning

Statistics for The Behavioral Sciences (MindTap C…

Statistics

ISBN:

9781305504912

Author:

Frederick J Gravetter, Larry B. Wallnau

Publisher:

Cengage Learning

MATLAB: An Introduction with Applications

Statistics

ISBN:

9781119256830

Author:

Amos Gilat

Publisher:

John Wiley & Sons Inc

Probability and Statistics for Engineering and th…

Statistics

ISBN:

9781305251809

Author:

Jay L. Devore

Publisher:

Cengage Learning

Statistics for The Behavioral Sciences (MindTap C…

Statistics

ISBN:

9781305504912

Author:

Frederick J Gravetter, Larry B. Wallnau

Publisher:

Cengage Learning

Elementary Statistics: Picturing the World (7th E…

Statistics

ISBN:

9780134683416

Author:

Ron Larson, Betsy Farber

Publisher:

PEARSON

The Basic Practice of Statistics

Statistics

ISBN:

9781319042578

Author:

David S. Moore, William I. Notz, Michael A. Fligner

Publisher:

W. H. Freeman

Introduction to the Practice of Statistics

Statistics

ISBN:

9781319013387

Author:

David S. Moore, George P. McCabe, Bruce A. Craig

Publisher:

W. H. Freeman

SEE MORE TEXTBOOKS