A survey is proposed to be conducted to know the annual earnings of the old Statistics graduates of Delhi University. How large should the sample be taken in order to estimate the mean monthly earnings within plus and minus dollar 10,000 at 95% confidence level? The standard deviation of the annual earnings of the entire population is known to be dollar 30,000.

A survey is proposed to be conducted to know the annual earnings of the old Statistics graduates of Delhi University. How large should the sample be taken in order to estimate the mean monthly earnings within plus and minus dollar 10,000 at 95% confidence level? The standard deviation of the annual earnings of the entire population is known to be dollar 30,000.

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

The operations manager at a compact fluorescent light bulb (CFL) factory needs to estimate the mean life of a large shipment of CFLs. The manufacturer’s specifications are that the standard deviation is 1,000 hours. A random sample of 64 CFLs indicated at sample mean life of 7,500 hours. Construct a 95% confidence interval estimate for the population mean life of compact fluorescent light bulbs in this shipment. Based on your confidence interval, make inference about the population parameter. Do you think that the manufacturer has a right to state that the compact fluorescent light bulbs have a mean life of 8,000 hours? Please explain. To answer these questions, is it compulsory to assume that the population compact fluorescent light bulb life is normally distributed? Why, why not. Suppose that the standard deviation changes to 800 hours. What are the answers for the first and second question?
An engineer designed a valve that will regulate water pressure on an automobile engine. The engineer designed the valve such that it would produce a mean pressure of 4.34.3 pounds/square inch. It is believed that the valve performs above the specifications. The valve was tested on 280280 engines and the mean pressure was 4.44.4 pounds/square inch. Assume the variance is known to be 0.640.64. A level of significance of 0.050.05 will be used. Make a decision to reject or fail to reject the null hypothesis. Make a decision.
High-power experimental engines are being developed by the Stevens Motor Company for use in its new sports coupe. The engineers have calculated the maximum horsepower for the engine to be 810HP . Sixteen engines are randomly selected for horsepower testing. The sample has an average maximum HP of 890 with a standard deviation of 85HP . Assume the population is normally distributed. Step 1 of 2 : Calculate a confidence interval for the average maximum HP for the experimental engine. Use a significance level of α=0.01 . Round your answers to two decimal places.
11:20 Section Two In a hospital the average time that a patient will wait to enter a clinic is normally distributed with a mean of 20 minutes. A random sample of 10 patients revealed the following waiting time: 21 19 18 18 20 22 23 25 17 20 Given the sample standard deviation S = 2.5 Assume that the researcher wants to test whether the mean time that a patient will wait is more than 20 minutes using a level of significance of 0.01. The value of t-critical is: * 4 points a. 2.330 O b. 2.764 c. 2.821 O d. 3.250
Is it true or false that the least absolute deviations (LAD) estimator minimizes the sum of the absolute value of the population errors.
In 2015, the average duration of long-distance telephone calls from a certain town was 9.4 minutes. A telephone company wants to perform a test to determine whether this average duration of long-distance calls has changed. Twenty calls, originating from the town, was randomly selected and the mean duration was 10.2 minutes with standard deviation 4.8 minutes. Construct the 99% confidence interval for the population mean duration of the long- distance calls from the town.
Trader Joes requires an area to have an average income of at least $45,000 to consider having a store. The Economics faculty at WKU constructed a 95% confidence interval for the average amount income of Bowling Green residents and computed this to be $26,000-$55,000. Which of the following statements is true? A. 95% of Bowling Green residents earn between $26,000 and $55,000 annually. B. 95% of Bowling Green residents in the sample to earn between $26,000 and $55,000 annually. C. With 95% confidence, we can say that Bowling Green residents earn between $26,000 and $55,000 annually. D. We are unable to determine without knowing the margin of error.
SCENARIO 3 Two samples each of size 25 are taken from independent populations assumed to be normally distributed with equal variances. The first sample has a mean of 35.5 and a standard deviation of 3.0 while the second sample has a mean of 33.0 and a standard deviation of 4.0. Referring to Scenario 3. the pooled (i.e., combined) variance is ________
A simple random sample with n = 54 provided a sample mean of 25.5 and a sample standard deviation of 4.4. (Round your answers to one decimal place.) (a) Develop a 90% confidence interval for the population mean. to (b) Develop a 95% confidence interval for the population mean. to (c) Develop a 99% confidence interval for the population mean. to
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.
A study was designed to compare the attitudes of two groups of nursing students towards computers. Group 1 had previously taken a statistical methods course that involved significant computer interaction. Group 2 had taken a statistic methods course that did not use computers. The students' attitudes were measured by administering the Computer Anxiety Rating Scale (CARS). A random sample of 1010 nursing students from Group 1 resulted in a mean score of 55.755.7 with a standard deviation of 7.97.9. A random sample of 1515 nursing students from Group 2 resulted in a mean score of 65.665.6 with a standard deviation of 6.16.1. Can you conclude that the mean score for Group 1 is significantly lower than the mean score for Group 2? Let μ1�1 represent the mean score for Group 1 and μ2�2 represent the mean score for Group 2. Use a significance level of α=0.05�=0.05 for the test. Assume that the population variances are equal and that the two populations are normally distributed. Step 3 of 4:…
Pls solve by using population correction