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Confidence Interval

Statistics: confidence interval, Margin of error, Sample mean, Population variance

1. A researcher wishes to estimate with 99% Confidence, the proportion of adults who have high-speed internet access. Her estimate must be accurate within 5% of the true Proportion. (a) Find the minimum sample needed, using a prior study that found that 54% of the respondents said they have high-speed internet access. (b) No p

Statistics: mean repair cost for washing machine; 10 bottles of cough syrup


Mean length in random sample of 79 bolts: 95% interval is?

In a random sample of 79 bolts, the mean length was 2.47 inches and the standard deviation was 0.09 inch. Use a normal distribution or a t-distribution to construct a 95% confidence Interval for the Mean. The 95% Interval is (__________, ________). Round to two decimal place.

Confidence interval: Take-out dinner, Grand Strand Medical, real estate, TV news

27. A recent study focused on the number of times men and women who live alone buy take-out dinner in a month. The information is summarized below. At the .01 significance level, is there a difference in the mean number of times men and women order take-out dinners in a month? What is the p-value? Statistic Men Women S

Statistics Intervals: Effect on costs for reduced length of patient hospital stay

Your hospital is negotiating with medical insurance providers, who would like to reduce the amount they pay as reimbursement for hospital stays. For a particular procedure, they would like to reduce payment by $300 and have patients go home one day earlier. To see what effect this would have one hospital costs, a random samp

Confidence intervals, null hypothesis for population mean weight loss

Attached is the data needed. 1. Test the null hypothesis that the population mean weight loss is zero versus the alternative hypothesis that the mean weight loss is greater than zero. use .05 and assume the population of weight loss is normally distributed. Also compute the p value. 2. What values of the sample mean we

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

Calculation of Confidence Interval

A researcher collected sample data for 17 women ages 18 to 24 . The sample had a mean serum cholesterol level (measured in mg/100 mL) of 188.8 , with a standard deviation of 5.5 . Assuming that serum cholesterol levels for women ages 18 to 24 are normally distributed, find a 90% confidence interval for the mean serum choleste

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

Interval Estimation

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

Confidence interval and hypothesis testing

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

Statistics Problem 4 and 40, Chapter 10; Problem C3, Chapter 10

See attached file. I need help understanding the problems on the attached spreadsheet. Below is my basic guidance. Please provide your answers in the attached spreadsheet. Problem 4, Chapter 10 This problem asks you to test a hypothesis concerning mean heights of Navy recruits. It specifically asks you to compute a t-s

Confidence Interval

You are given the sample mean and the sample standard deviation. Use this information to construct the 90% and 95% confidence intervals for the population mean. Which interval is wider? If convenient, use the technology to construct the confidence intervals. A random sample of 42 eight-ounce servings of different juice drinks h

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 6: 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