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Confidence Interval

Confidence interval for the true population proportion

A citizen's group is interested in the portion of the population that opposes the expansion at O'Hare airport. In a survey of 1,440 randomly selected people, 1098 people opposed the expansion. Construct a 95% confidence interval for the true population proportion.

Construct confidence interval

A study of 64 convicted felons was conducted regarding the age of the first offense. The mean age of first offense was 13.2 years with a s.d. of 4.6 years. Construct a 94% confidence interval for the mean age of the first offense for all convicted felons and graph.

Statistics problems

Please use excel when necessary: 1)The GMAT scores of MBA candidates are normally distributed with a mean of 568 and Standard eviation of 25.6 What is the probabilitie of candidates scoring higher than 600 ? 2) A financial Manager is interested to study DM students. A random sample of 256 students salaries totaled $ 9,067,

Determining confidence co-effiecents

Olive Garden Swiss Chalet Sample size 50 45 Sample mean $22 $18 Standard deviation $3.00 $3.25 How do I create interval estimate for the difference between the average fees of the 2 restaurants at a confidence co-effiecent at 95 % What do I need to do to find o

Confidence interval (Multi choice)

It is desired to estimate which of the two soft drinks, Coke or Pepsi, UCLA students prefer. A random sample of 167 UCLA students produced the following 95% confidence interval for the proportion of UCLA students who perfer Pepsi: (.344, .494) A. Is this a large enough sample for this analysis to work? aa) Yes, since N=167, whic

Confidence interval (Multi Choice)

Currently the stock market is declining. A stock broker wishes to determine his portfolio. She randomly choose 64 daily stock prices for stock A from the past year data, and obtain the 95.44% confidence interval for the average price to be [ $30.0 , $40.0] A. What is the confidence coefficient? aa) 50% bb) .9544 cc) 40.00 dd) $3

Statas

What is the predicted value for x = 10, if the regression equation is: y' = 106.8 - 3.1x? If alpha/2 = 0.02, the confidence interval is the ______% confidence interval. The Academy of Orthopedic Surgeons states that 80 out of every 100 women wear shoes that are too small for their feet. A researcher wants to be 98% c

Statistical Research Problem

Note: Moved from STATS to MATH because more OTAs available in the latter category. NOTE: I DO NOT WANT ANYONE TO WRITE MY PAPER I JUST NEED 5-6 TECHNIQUES TO INCLUDE IN MY PAPER and I'm unsure which ones are best to use: Here is the outline listing what I need to include as well as the first page of my proposal summary a

Confidence Interval

See Attached file in "Word". Please show all work and give a full detailed explaination of answer. Thank you.

Confidence interval

A music teacher asks six randomly selected students how many hours per week they practice their instrument. the teacher receives the following answers:10,12,8,9,16,5. Find a 90% confidence interval for the average length of time that a student pratices each week.

Confidence Interval

It has been determined that the correlation between a very good predictor variable and college GPA is .69. Also, the standard error of the estimate is .54 based on the four point grading scale. If a student should expect a 2.75 GPA, what are the 95% expectations for the student?

Confidence interval

A quality control inspector is concerned with the average amount of weight that can be held by a type of steel beam. A random sample of five beams is tested with the following amounts of weight added (in thousands of pounds): 9, 11,10,10,8 Assuming the population is distributed normal, construct a 95% confidence interval

3844-Statistical positioning

Assume that federal regulations require that the average smoke stack concentration of a certain industrial pollutant must not exceed 135 ppm. The EPA suspects one factory is in violation.The EPA randomly collects 31 independent specimens of smoke from the factory smokestack,one for each day in October and performs extensive anal

Construct the confidence interval

Construct the confidence interval. Requires either the use of t distribution or the normal distribution. Hospital costs for accident victims who wore seatbelts. 20 randomly selected cases have a distribution that appears to be bell-shaped with a mean of $9004 and a standard deviation of $5629. Construct the 99% confidenc

Use the degree of confidence and sample data

Use the degree of confidence and sample data to find a) the margin of error and b) the confidence interval for the population mean u. Assume the population has a normal distribution. Salaries of pilots: 99% confidence; n=12, mean of values in sample = $97,334, s= $17,747

Construct the 99% confidence interval

4400 students surveyed about length of time to complete bachelor's. The mean is 5.15 years and the standard deviant is 1.68 years. Based on these sample data, construct the 99% confidence interval for the mean time required by all students.

3758-stats

Details: The estimated value of a population mean is $120, and the upper limit of the 90% confidence interval is $140. A 95% confidence interval has also been constructed. Given this information, which of the following best describes the lower limit of the 95% confidence interval?

Statistics - confidence intervals

The average weekly earnings for women in managerial and professional positions is $685 with a standard deviation of $45. Salaries are normally distributed. Answer the following questions. a. What is the probability that a woman will have a weekly salary of more than $650? b. What is the probability that a woman will hav

Confidence interval, error of estimate, sample size

In the publication Employment and Earnings, information on the ages of people in the civilian labor force was published. Seventy-five people in the civilian labor force are randomly selected. The mean age is 37.4 years with a standard deviation of 10.3 years. a. Find the 99% confidence interval for the mean age. b. W

Use given degree of confidence and sample data

Use given degree of confidence and sample data to find a) margin of error E and b) the confidence interval for the population mean mu. Starting salaries of college graduates who have taken a statistics course: 95% confidence; n=100, mean of the values in a sample (x with line above)= $43,704, s= $9879.

Refer to the OECD data, which reports information on census, economic, and business data for 29 countries. a. Develop a 90 percent confidence interval for the mean percent of the population over 65 years. b. Develop a 90 percent confidence interval for the mean energy use.

Details: Refer to the OECD data, which reports information on census, economic, and business data for 29 countries. a. Develop a 90 percent confidence interval for the mean percent of the population over 65 years. b. Develop a 90 percent confidence interval for the mean energy use.

What is the lower/upper limit of the 99% confidence interval?

To estimate the percentage of a species of rodent that carries a specific viral infection, 150 rodents are randomly selected and examined, and 76 of them are found to be infected. Based upon this, find a 99% confidence interval for the proportion of all rodents of this species that are infected with the virus. Then complete the

Standard deviation, confidence interval

1. When the level of confidence and sample standard deviation remain the same, a confidence interval for a population mean based on a sample of n=100 will be ______ a confidence interval for a population mean based on a sample of n=50 a) wider than b) Narrower than c) equal to Explain answer: 2). If the box wei

Confidence interval for population variance

A random sample of size 9 of a random variable X gave a variance of 3.0. Find a 95% confidence interval for the population variance, assuming that X is normally distributed.

A confidence interval of the mean is determined.

This problem is solved: Let's summarize the method for finding the 95% confidence interval using a step-by-step illustration. Suppose that a certain automobile company wishes to determine the expected miles per gallon for one of its new models. Based on years of experience with cars, the company statistician realizes that not