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Confidence Interval

Estimation, ANOVA: TV watching by students, motor skills of children, T-test

1. Explain why it would not be reasonable to use estimation after a hypothesis test for which the decision was "fail to reject Ho. 2. An elementary school principal would like to know how many hours the students spend watching TV each day. A sample of n = 25 children is selected, and a survey is sent to each child's parents.

Hypothesis Testing & Confidence Interval : Solution set

See the attached is an excel spreadsheet with the necessary information to complete the problem. I am doing a study on alcohol consumption between males and females (two independent samples continuous outcome)this is my hypothesis: H1: = Men are able to consume more alcoholic beverages than women Ho:= Men and

Large Coverage Errors for Interviewers Bias

1) A poll is planned to determine what proportion of all students favor an increase in fees to support a new track and field stadium. A questionnaire will be published and the first 1000 completed questionnaires will be analyzed. Which of the following errors will be associated with the sample? A. Only non-sampling errors

A sample from a 1,591-page phone directory; unpopped kernels of popcorn

1) A sample of 20 pages was taken without replacement from the 1,591-page phone directory Ameritech Pages Plus Yellow Pages. On each page, the mean area devoted to display ads was measured (a display ad is a large block of multicolored illustrations, maps, and text). The data (in square millimeters) are shown below: 0 260 356

Extra Credit work

Number 1 The union for a particular industry has determined that the standard deviation of the daily wages Find a 90% confidence interval for the true mean daily wage of all union workers in the industry. Then complete the table below. Carry your intermediate computations to at least three decimal places. Round your answers

Confidence interval: Use of Blackberries by students at OSU

Suppose you have drawn a simple random sample of 225 students from OSU. In this sample, 45 students own Blackberries. Let π denote the proportion of OSU students who own Blackberries. Construct a 95% confidence interval for π. Suppose you have drawn a simple random sample of 100 students from OSU and recorded

Variance, estimator for mean, millionaire net worth

#1 Suppose you are sampling from a population with mean µ = 1,065 and standard deviation σ = 500. The sample size is n = 100. What are the expected value and the variance of the sample mean X? Show and explain your work (study guide # 5-41). #2 Suppose a new estimator for the population mean is discovered. The new

Confidence Intervals

Please help me create and interpret the confidence intervals- 90%, 95%, and 99%.. 1)Compute the confidence interval(s) for the attached data (data and graphs)Distance only. 2)Provide graph and table in excel 3)Based on the confidence interval(s), determine if you would change the conclusion that distance does affect a home

Point Estimates & Confidence Interval

A simple random sample of 8 employees is selected from a large firm. For the 8 employees, the number of days each was absent during the past month was found to be 1, 3, 3, 3, 1, 5, 4, and 3 (a) What is the point estimate for , the mean number of days absent for the firm's employees? Round your answer to nearest hundredth. =

Confidence interval

A human resource manager for Carver County is evaluating a recent effort to improve the health of the county's firefighters by providing an exercise room in each of the county's firehouses. Their records prior to installing the exercise rooms indicate that the mean weight of all county firefighters is 198 pounds with a standard

Hypothesis Testing and Confidence Interval Problem

A. *HT* A test was conducted to compare the wearing quality of the tires produced by two tire companies. A random sample of 16 cars is equipped with one tire of Brand X and one tire of Brand Y (the other two tires on each car are not part of the test), and driven for 30 days. The following table gives the amount of wear in thous

Statistcs: Phone Directory and Popcorn Kernels Statistics

Question 1: A sample of 20 pages was taken without replacement from the 1,591-page phone directory Ameritech Pages Plus Yellow Pages. On each page, the mean area devoted to display ads was measured (a display ad is a large block of multicolored illustrations, maps, and text). The data (in square millimeters) are shown below:

Standardized test of manual dexterity

You have administered a standardized test of manual dexterity to two groups of 10 semi skilled workers. One of these two groups of workers will be employed by you to work in a warehouse with many fragile items. The higher the manual dexterity of a worker the less likelihood that worker will break significant inventory. Because o

Confidence Interval

(1) The lifetime of a certain brand of battery is known to have a standard deviation of 19.8 hours. Suppose that a random sample of 50 such batteries has a mean lifetime of 40.9 hours. Based on this sample, find a 95% confidence interval for the true mean lifetime of all batteries of this brand. Then complete the table below.

Statistics: Set of five questions

See attached file for 5 questions: Mean weight of carry-on luggage Mean of a population Lifetimes of washing machines Proportion of Democrats in sample of registered voters Proportion of customers who use stor credit card for purchases In order to determine the average weight of carry-on luggage by passengers in airpla

Statistics Problems

1. Find the indicated critical z value. Find the value of zα/2 that corresponds to a confidence level of 97.80%. 2. Find the appropriate minimum sample size. You want to be 95% confident that the sample variance is within 20% of the population variance. 4. Express the confidence interval using the indica

Confidence Interval for Mean Blood Pressure

A researcher wishes to determine whether people with high blood pressure can reduce their blood pressure by following a particular diet. Use the sample data below to test the claim that the treatment population mean mu_1 is smaller than the control population mean mu_2. Test the claim using a significance level of 0.01. You m

Statistics Module: Correlation and Regression

Module 6: Correlation and Regression A For the supermodel dataset at the right, treat height as the explanatory variable and weight as the response variable. (Data set is given in the excel file) 1 Is there a significant correlation? Show the null hypothesis, df and the test you used. yes/

Confidence Interval and Hypothesis Test

1. A sample of 35 golfers showed that their average score on a particular golf course was 80 with a standard deviation of 6. Answer each of the following (show all work): (A) Find the 95% confidence interval of the mean score for all 35 golfers. (B) Find the 95% confidence interval of the mean score for all golfers if this

Confidence Interval & Sample Size for a Random Sample

1 (b). A survey of a random sample of 250 car commuters indicates that 80 would switch to commuting by public transport if they had to pay at least $10 per week for parking at their work places. (i) Using a 95% confidence level, calculate the confidence interval for the proportion of the commuters who might be expected to ch

Statistics: Confidence Interval for Mean

* The UNITE/MORI 2004 survey of student experiences estimated that university students in the UK paid on average $54 per week in accommodation costs. Assume that this average is based on a sample 755 students and that the population standard deviation for weekly accommodation costs is $ 11. a. Construct a 90 per cent confi

Assessing Sample Size for the Number of "Walk-Ins"

Part of my job description is to teach Recruiters their daily individual tasks and how to properly manage their time. One of the Recruiter duties is to generate appointments in many different ways. They can visit high schools, Shopping Centers, or any other public places available within their Recruiting zone; their main goal

Confidence Interval

1. In each of the following exercises, a set of condition is given. To construct a 95 percent confidence interval for the population mean, would you use the z distribution, a t distribution, or neither? Where appropriate, determine the z or t value. n = 21, xbar = 23.1, s = 7.5, population distribution shape normal, σ = 7.

Confidence interval

A machine produces 9 inch latex gloves. A sample of 85 gloves is selected, and it is found that 36 are shorter than they should be. Find the 98% confidence interval on the proportion of all such gloves that are shorter than 9 inches

Find confidence interval

Use the given degree of confidence and sample data to find a confidence interval for the population standard deviation o. Assume that the population has a normal distribution. Weights of men: 90% confidence; n=14, Xbar=160.9lb, s=12.6lb


Week 8: ________________________________________ There are 2 pages in this exam. Be sure to complete all pages before submitting the exam. Page: 1 2 ________________________________________ Time Remaining: 1. (TCO 9) What is the feasible range for r, the correlation coefficient? (Points: 6) 0 to 1

Confidence Interval: Nursing school alumi & Auditor for bank

A nursing school wants to estimate the true mean annual income of its alumni. It randomly samples 200 of its alumi. The mean annual income was 55,200 with a standard deviation of 1,500. Find the 95% confidence inteval for the true mean annual income of the nursing school alumni. 2. An auditor wants to estimate what proporti


() is a pi symbol. 2. In the next presidential election of year 2012, five candidates running for the election are Sarah Palin, Hilary Clinton, Barack Obama, Mitt Romney, and Rudy Giuliani. It is desired to estimate the true proportion ( ) favoring one of the five candidates. a) based on sample size 1000 with 92% confidence,

Confidence Interval for ISO Certification

In a random sample of 100 manufacturing firms, 67 indicated that their company attained ISO certification within the last two years. Find a 95% confidence interval for the population proportion of companies that have been certified within the last two years. In solving the above question you must write the formula of the confide