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Confidence Interval

Confidence Intervals and Hypothesis Test.

The mean and standard deviation of the sample of 65 customer satisfaction ratings are x-bar = 42.95 and s = 2.6424. If we let "mu" denote the mean of all possible customer satisfaction ratings: a) Calculate 95 and 99 percent confidence intervals for "mu". b) Using the 95 percent confidence interval, can we be 95% confident

Sample Mean / Mean of Population

Vito has completed the analysis of some sample data from a recent survey of local high school students. He has determined that his sample has attended an average of 145 days of school this year, with a standard error of the average of 8 days. The sample was random and fairly large. (refer to document attached for other given inf

If you promised to deliver a survey that is accurate plus minus 5% at a confidence level of 90%, can you say, using a conservative basis for estimation, that you have reached your objective?

Having been retained by the National Native American Political Party to conduct a poll of residents of Muscogee, Oklahoma, you have worked diligently on completing interviews with residents of that town for three weeks. Your budget of $10,000 is expended. You have completed 270 interviews. (A) If you promised to deliver a su

Confidence Intervals

Decoders often use the fact that the letter "e" appears in written work more than any other letter. Make a photocopy of an article in a newspaper or magazine {see article below}. Choose two different paragraphs from that article/page (must be a minimum of 25 words in each paragraph and the paragraphs must contain the letters e a

Confidence Intervals

Suppose an SRS of 25,000 Americans were surveyed and 16,000 of them said they have blue colored eyes. a) Create a 98% confidence interval estimator for the population proportion of Americans that have blue colored eyes. b) What is the minimum sample size that would be required to estimate the population's proportion to wi

Confidence Intervals

To estimate the mean size of maple trees in a certain area of the Adirondacks. A sample of 15 maple tree heights is collected (refer to the data set). Data Sheet numbers: 50, 41, 31, 33, 47, 39, 41, 44, 39, 32, 35, 43, 37, 49, 51 a) Determine a 90% confidence interval for the population mean of maple tree heights.

Confidence Intervals

8.20 425 510 629 236 654 200 276 501 811 332 424 674 676 694 710 662 633 a. Find a 90% confidence interval for the mean number of tongue flicks per 20 minutes for all juvenile common lizards. Assume a population standard deviation of 190.0 (note: The sum of the data is 9047.) b. interpret your answer from part (a)

Normal Distribution, Mean and Standard Deviation

7.40 A variable of a population has a mean of m = 35 and a standard deviation of o = 42. a. If the variable is normally distributed, identify the sampling distribution of the sample for samples of 9. b. Can you answer part (a) if the distribution of the variable under consideration is unknown? Explain your answer. c. C

Test of hypothesis, Confidence Interval

1) Recruit 25 volunteers who have recieved a medication and find they have a mean concentration of 7 with a standard deviation of 2. Assume normall ditributed. FIND: 95% CONFIDENCE INTERVAL for pop mean concentration Find: 99% confidence interval for pop var of conc HOW large a sample os needed to ensure the length of the

Confidence Intervals

In the atmosphere, the ratio of toxic gas, for a given volume of air, is a normally distributed random variable with mean μ and variance σ² which are unknown. We take n samples, whose values are X1, X2,..., Xn. Please see attachment for questions 1, 2, and 3.

Confidence Intervals, Samples, and Unknown Variance

Let (X1, X2,..., Xn) be a sample, where each Xi is a random variable of normal distribution with mean mu and variance sigma². Let us suppose that n = 20, and sigma² = 9. An experiment has yielded the results (X1, X2,..., X20), and we have calculated that the empirical mean x20 = 2.09. 1) Give a confidence interval with leve

Probability Confidence Intervals

I am currently studying probability and am having a bit of trouble with the following questions. Can you help me? If you can, thank you very much. The questions are: 1.) An office manager wishes to estimate the mean time required to handle customer complaints. A sample of 38 complaints shows a mean time of 28.7 minutes with a

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


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