A sample of 15 students was used to estimate the performance of graduates of a certain college on a standardized test taken by all the students of the college. It was found that the sample average score of these 15 students on the test was 85 with a sample standard deviation of 15. What would be the 95% confidence interval for the average score of the whole college population? If instead, it is known that this sample of 15 students was taken only from a specific section of a class containing 30 students, what would be the

A sample of 15 students was used to estimate the performance of graduates of a certain college on a standardized test taken by all the students of the college. It was found that the sample average score of these 15 students on the test was 85 with a sample standard deviation of 15. What would be the 95% confidence interval for the average score of the whole college population? If instead, it is known that this sample of 15 students was taken only from a specific section of a class containing 30 students, what would be the

ENGR.ECONOMIC ANALYSIS

14th Edition

ISBN:9780190931919

Author:NEWNAN

Publisher:NEWNAN

Chapter1: Making Economics Decisions

Section: Chapter Questions

Problem 1QTC

See similar textbooks

Similar questions

1. A survey on student behavior in some major College in Oman asked a randomly selected group of 300 students on the number of hours a week he/she reads a newspaper. The sample mean was 4.5 and standard deviation 2.9. We can assume that the underlying distribution of number of hours reading newspaper is approximately normal. a) What will be a 95% confidence interval of the population mean number of hours a College student read newspapers per week ? Interpret the same. b) Suppose you perform a similar survey at CAS, Nizwa with 35 randomly selected students; the sample mean and sample standard deviation were 5.1 and 2.6 respectively. What will be a 95% confidence interval of the population mean number of hours an CAS, Nizwa student read newspapers per week ? Interpret the interval in the context of the problem. Solve a and b
Is it true or false that the least absolute deviations (LAD) estimator minimizes the sum of the absolute value of the population errors.
A psychologist wants to estimate the variance of employee test scores. A random sample of 18 scores had a sample standard deviation of 10.4. Find a 90% confidence interval for the population variance. What assumption if any have you made in calculating this interval estimate?
True or False? When the population variance is unknown and the size of a random sample is 20, then the student’s t used to construct a 90% confidence interval for the population mean is 1.729, by Appendix D.
Of 900 people treated with a new drug, 180 show allergic reaction. Construct a 98% confidence interval for the true proportion of the population who would show an allergic reaction.
A hypothesis will be used to test that a population mean equals 9 against the alternative that the population mean is less than 9 with known variance . What is the critical value for the test statistic for the significance level of 0.025? Round your answer to two decimal places (e.g. 98.76).
According to R.L. Polk & Co., Americans held onto their new vehicles for an average of 71.4 months. A random sample of 60 adults who recently sold their new vehicle was selected. Assuming the standard deviation for this population is 15.8 months, the standard error for this sample is
12 A researcher reports survey results by stating that the margin of error for the 95% middle interval of the sample means is 44.75. The population variance is assumed to be σ² = 18750. The sample size used in this survey is ________. a 53 b 44 c 36 d 31
A service counter manager wishes to ensure that an average of 16 seconds toserve a customer. In order to analyse the efficiency of the service process, he takesa random sample of 56 customers. The mean service time of the sample is 15.8seconds. Assume that the population standard deviation is 0.8 seconds. (a) State the null and the alternative hypotheses for the test (b) Use the p-value approach to test the manager's concern at ? = 0.05. (c) Confirm your result in (ii) by using the critical value approach. (d) State the recommendation that the manager can present to the company.
As the sample size increases, the variance of the sample mean Select one: a. increases b. not enough info to know c. decreases d. stays constant
In 2015, the average duration of long-distance telephone calls from a certain town was 3.9 minutes. A telephone company wants to perform a test to determine whether this average duration of long- distance calls has changed. Fifty calls, originating from the town, was randomly selected and the following summary minutes. ∑ ? = 205 ∑(? − ?̅)2 = 56.43 Calculate the sample mean, ?̅. Calculate the sample standard deviation.
According to the Annual survey of drugs expenditure in country X, the annual expenditure for prescription drugs is $838 per person in the Northeast region of the country. A sample of 60 individuals in the Midwest shows a per person expenditure for prescription drugs of $745. Further, it is given that the population standard deviation of $300. Formulate hypotheses for a test to determine whether the sample data support the conclusion that the population annual expenditure for prescription drugs per person is lower in the Midwest than in the Northeast and Identify whether it is a two-tail test or a one tail test (Left or right tail).