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Confidence Interval

Statistics: Problems

1. For a t distribution with 16 degrees of freedom, find the area, or probability, in each region. a. To the right of 2.120. (Use 3 decimals.) __________ b. To the left of 1.337. (Use 2 decimals.) __________ c. To the left of -1.746. (Use 2 decimals.) __________ d. To the right of 2.583. (Use 2 decima

Confidence Interval and Power of a Test

On 10 leases on the outer continental shelf in the Gulf of Mexico in 1984, Atlantic Richfield submitted bids. The bids are given below: 14.27, 14.60, 14.98, 15.25, 15.30, 15.42, 15.50, 15.72, 15.83, and 15.92. The x(mean)=15.279 and the s=.532. Assume that these bids are normally distributed. Place a 95% two sided confidence

Confidence Interval Estimate for absentism among clerical workers

The personnel director of a large corporation wished to study absenteeism among clerical workers at the corporation's central office during the year. A random sample of 25 clerical workers reveals the following: Absenteeism: X= 9.7 days, S = 4.0 days 12 clerical workers were absent more than 10 days A. Construct a 95% c

Margin of Error

Chapter 7 - Section 2 Problem 20 Finding Margin of Error. Assume that a sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level. 90% confidence; the sample size is 1780, of which 35% are successes. Problem 30 Gender Selection

Statistics: Confidence Interval for the Scribe's use of caffeine

Confidence Interval or the lack of it... It is the year 1581 A.D. At the Renaissance University (RU), I am the appointed CPA, Coffee Pot Attendant. It is a very important office sponsored by the Head Scribe. I have taken this job very seriously, because I believe that I am the key to increased productivity of scribes at

Statistics: Chapter 7 and 8 problems

See attached file. Chapter 7, problems 7.22, 7.23, 7.24, 7.25 Chapter 8, problems 8.32, 8.33, 8.61, 8.67 7.22. The US Census Bureau announces that the median sales price of new houses sold in March 2006 was $224,200 while the mean sales price was $ 279,100. Assume that the standard deviation of the prices is $ 90,000.

Hypothesis Testing & Confidence Interval Sample Errors

Consider that 10 observations were selected from a normal population whose variance is 64. Observations are: 58, 62, 45, 50, 59, 65, 39, 40, 41 and 52. Check to 5% (.05) level of significance if there is sufficient evidence to conclude that the average population is 45. Calculate the sample average. Calculate the standard

Sample Size and Probability

1 ) Management has asked a lab to produce accurate results at the 88% level for a first time experiment. the management wants the final error to be within 1/10th of the sample standard deviation. Find the sample size. 2) A sample of 16 women had a mean score of 275 and a variance value of 360. A. find both the 955 and 99

ElecMart: Two sided confidence intervals fo customers' orders

See attached data file. Problem (P_Data on the template) contains data for 400 customers. This company, ElecMart sells electronic appliances for mail-in orders. Consider this data as a random sample from all of ElecMart mail-in orders. Find the following two sided confidence intervals: a. Find the 95% Confidence Inter

Confidence Interval: Difference in Proportion

Borst investigated the relation of ego development, age, gender, and diagnosis to suicidality among adolescent psychiatric inpatients. Their sample consisted of 96 boys and 123 girls between the ages of 12 and 16 years selected from admissions to a child and adolescent unit of a private psychiatric hospital. Suicide attem

Two Populations confidence intervals for Maxforce, Inc.

Maxforce, Inc., manufactures racquetball racquets by two different manufacturing processes (A and B). Because the management of this company is interested in estimating the difference between the average time it takes each process to produce a racquet, they select independent samples from each process. The results of the samples

Case Problem with data Set.

Please see the attached problem with data set. Full view in book found here: See the description here. It

Confidence Interval for Proportion

On January 7, 2000, the Gallup Organization released the results of a poll comparing the lifestyles of today with previous times. The survey results were based on telephone interviews with a randomly selected national sample of 1,031 adults, 19 years and older. a. Gallup found that 42 percent of the respondents said that they

Decision Analysis in EXCEL

Please see attached files for further information. 1. A toy company has developed a new toy for the upcoming Christmas season. Since this toy is considerably different from the ones it has manufactured previously, the company will need to develop a new production facility for it. Three facility sizes-small, medium, and large-

P-Value - Null Hypothesis - Productivity Data for plant worker productivity

See attached file. 11.51. A plant manager has collected productivity data for a sample of workers, intending to see whether there is a difference in the number of units they produce on Monday versus Thursday. The results (units produced) are in data file XR11051. Using the 0.01 level of significance, evaluate the null hypothe

Confidence Interval for Proportion: Defective dolls

A shipment of 500 dolls is received by Panda Importers. The quality control manager selects a random sample of 75 to test. Five are bound to be defective. Construct a 90 percent confidence interval for the population proportion of defective dolls in the shipment. Ans should be 0.06666 + / - 1.645 sqrt (0.667 (1-0.667 / 75

Mean weekly child care cost for employees

Merrill Lynch Securities and Health Care Retirement, Inc., are two large employers in downtown Toledo, Ohio. They are considering jointly offering child care for their employees. As apart of the feasibility study, they wish to estimate the mean weekly child-care cost of their employees. A sample of 10 employees who use child car

Confidence Interval, Interval Estimates, Finite Population

SEE ATTACHED FILE - Sample Size, Finite Population (9.110) NOTE: Please use an Excel spreadsheet for response. Please do not just provide the answer but show in complete detail how you arrived at the answer, step-by-step, from the beginning to the end of the solution.

Confidence interval for µ based on raw data and ? known for paint samples

See the attached Excel spreadsheet and 2 files which may be of assistance in determining the Mean. The spreadsheet contains the amount of fluid ounces of each of the 40 paint cans. NOTE: Please use an Excel spreadsheet for response. Please do not just provide the answers but show in complete detail how you arrived at the ans

Confidence Interval Estimates for Means

A simple random sample of 25 has been collected from a normally distributed population for which it is known that ? = 17.0. The sample mean has been calculated as 342.0, and the sample standard deviation is s = 14.9. Construct and interpret the 95% and 99% confidence intervals for the population mean. NOTE: Please use a

Hypothesis Testing & Confidence Interval: Mean sleep

See data file attached. Compare the mean of the "Sleep" data to the national average of 6.9, with a standard deviation of 1.38. Perform the following statistical operations using a Microsoft Word document: State a research (directional) hypothesis and the null hypothesis about the populations Determine the cutoff sampl

Confidence Interval Problem: Delivery Truck Manager Example

A delivery truck manager takes a sample of 25 delivery trucks and calculates the sample mean and deviation for the cost of operation. A 95% confidence interval for the mean cost is constructed and found to be $253 to $320. He reasons that this interval contains the mean operating cost for the fleet of delivery trucks since the s

Statistics Part III for Managers: 4 problems

1. If you want to be 95% confident of estimating the population portion to within a sampling error of + 0.02 and there is historical evidence that the population proportion is approximately 0.40, what sample size is needed? 2. In a study of 500 executives, 315 stated that their company informally monitored social