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    Confidence Interval

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    Compute a 95% confidence interval for the difference in mean scores

    An investigator at a nearby university wants to find out from a recent "math skills" test if there is any difference in scores between full-time and part-time students. Records show the following: Student Mean Score Standard Deviation Number Full-Time 83 12 45 Part-Time 70 15 55 Compute a 95% confidence

    Estimation

    In an election campaign, the party vying for an upset polls a sample of 100 voters. The party finds that 60 of 100 clearly express the intention of voting in favor of the party polling. How many voters should be sampled if the party wants to estimate the population proportion with a sampling error of 5% or less? (Use confide

    Confidence interval for the difference of proportions

    Please help with the following problem. Provide step by step calculations. After a certain candidate announced his intention for running for the premiership of a province, many polls were conducted to assess his chanced for success. Among them were two polls of independant samples taken from two populations. The poll in the

    Confidence Interval

    Please see the attached file for full problem description. --- corporation that maintains a large fleet of company cars for the use of its sales staff is interested in the mean distance driven monthly per sales person. The following table gives the monthly distances in miles driven by a random sample of sales persons: 261

    Limits of Confidence Interval

    The following data were randomly drawn from an approximately normal population. 24, 25, 28, 31, 34, 38 Based on these data, find a confidence interval for the population standard deviation. Then complete the table below. Carry your intermediate computations to at least three decimal places. Round your answers to at least

    From a large number of actuarial exam scores...

    From a large number of actuarial exam scores, a random sample of scores is selected, and it is found that of these are passing scores. Based on this sample, find a confidence interval for the proportion of all scores that are passing. Then complete the table below. Carry your intermediate computations to at least three d

    Confidence intervals and prediction intervals

    Day 1 dose 123 Day 2 dose 139 Day 3 dose 85 Day 4 dose 133 Day 5 dose 91 Day 6 dose 110 Day 7 dose 118 What is the 95% one-sided confidence interval for the average worker? What is the 95% predicted dose for a 95% one-sided confidence interval?

    A sample problem is solved.

    Given the following information, calculate a confidence interval using a 95 percent confidence level: sample proportion =.4, standard error of the proportion =.05, and sample size =100.

    Confidence intervals and hypothesis testing? Maybe?

    A local merchant is interested in obtaining a small business loan to expand his business. He will be able to obtain a more favorable interest rate if he can reasonably demonstrate that his near-term monthly revenues will be between $10,000 and $15,000. He doesn't know the exact level of sales to expect over the next several mo

    Probability and decision making

    Norm Dickins the town pharmacist is interested in obtaining a loan to expand his business. He will get a better interest rate if he can reasonably demonstrate that his near-term monthly revenues will be between $10,000 and $15,000. He doesn't know the exact level of sales to expect over the next several months, but based on pa

    Confidence Intervals

    A cutoff score of 79 has been established for a sample of scores in which the mean is 65. If the corresponding z-score is 1.4 and the scores are normally distributed, what is the standard deviation?

    Confidence Interval for the Mean Weight of Samples

    How do you figure a 90% confidence interval for the mean weight of all Siberian tigers in captivity from various zoo's, where the random sample is 31, the mean weight is 507 pounds from sample zoo's, with a standard deviation of 62 pounds?

    Confidence Interval

    Which of the following is not needed to be known to calculate a confidence interval? a. standard deviation b. sample size c. mean d. degree of confidence

    Confidence Interval and Statistical Analysis

    Find the confidence interval and conduct statistical analysis for the given problems. 6. A producer of a juice drink advertises that it contains 10% real fruit juices. A sample of 75 bottles of the drink is analyzed and the percent of real fruit juices is found to be 6.5%. If the true proportion is actually .10, what is th

    Probability/Confidence Level

    1) Megacorp wants to determine whether the mean of all one-day travel expenses in Moscow exceeds $500. A simple random sample of 35 one-day travel expenses is obtained from Megacorp travel expense files. The average one-day Moscow expense was found to be $538 with a standard deviation of $41. a) Calculate the probability of

    Statistic problem

    2 Questions: 3) Using the CIELO data, calculate 95% and 99% confidence intervals for the percentage intending to purchase the CIELO. (see attachment for full question) -------------------------------------------------- 3) Using the CIELO data, calculate 95% and 99% confidence intervals for the Percentage intending to purcha

    Confidence interval, Testing of Hypothesis

    1)      Calculate 95% and 99% confidence intervals for the means selling price of Vehicles sold by Winter Pontiac. 2)      Test the hypothesis that the mean selling price of automobiles sold by Winter Pontiac is less than $25,000. Use alpha= .05 To solve the problem 1 and 2 below use the following table

    Statistics - Confidence Interval

    Please provide step by step instructions using actual numbers instead of formulas for solving the following 3 problems, thanks 3. Determine whether the average number of calories in a homemade cookie is more than a store-bought one. Estimate the difference in the mean calories between the two types using a 90% confidence int

    Confidence interval level

    I have an opinion poll perfomed on 2 different population sizes, 900 and 10,000 with a 95% confidence level (Confidence Interval details have been computed) for each population. Opinion Poll Surveyed 900 Surveyed 10000 Invalid intelligence 52% 468 Invalid Intelligence 52% Proportion 0.52 Proportion 0.52

    Calculating a confidence interval using EXCEL

    I need to know how to do this using microsoft excel. Do not address this unless you can do it in EXCEL. thank you Dunkin Donuts advertises that a dozen of their donuts weighs about 43 oz. A certain baker has figured out that she can stay out of trouble with her manager if each donut weighs about 3.6 oz. To test her donut-mak

    Test a Hypothesis and Confidence Interval

    Case Analysis: Riverside Chamber of Commerce ABC Corporation of California publishes a variety of statistics, including the number of individuals who got a new job during the past 12 months and the mean length of time the individuals have been on the job. The Statistical Analysis Department of ASBC Corporation reported that th

    Statistics

    4.) 20 rivets out 100 in a new box that we tested had break strength below the desired level. Since this is a critical part for assembly, we want to be 99% confident of how many rivets are below the desired level. Calculate the confidence interval of the percentage of rivets that are below the desired level. 5.) We expect a 1

    Statistics: Confidence Interval and Decision Making

    Tourism is one consideration for CoffeeTime's future. A survey of 1,233 visitors to Mumbai last year revealed that 110 visited a small café. Use a 0.05 significance level to test her claim. Would it be wise for her to use that claim in trying to convince management to increase their advertising spending to travel agents? Ex

    Comparisons Involving Proportions and a Test of Independence

    Does age make a difference in the amount of savings a worker feels is needed to be secure at retirement? A study by CommSciences for Transamerica Asset Management found that 0.24 of workers in the 25-33 age category feel that $250,000 to $500,000 is enough to be secure at retirement. In the 34-52 age category already 0.35

    Confidence intervals for one population mean

    For a t-curve with df = 8, find each t-value and illustrate your results graphically. a.The t-value having area 0.05 to its right. b. t 0.10 c.The t-value having area 0.01 to its left (hint: A t-curve is symmetric about 0.) d.The two t-values that divide the area under the curve into a middle 0.95 area and two outsid

    Test whether the sample has been drawn from the population.

    A Variable has a mean of 100 and a standard deviation of 16. Four observations of this variable have a mean of 108 and a sample standard deviation of 12. Test whether the sample has been drawn from the population. a. Standardized version of x (sample mean). b. Studentized version of x (sample mean).

    Statistics

    5. Human body temperatures are normally distributed with a mean of 98.6 degrees F and a standard deviation of 0.72 deg. F. Find the temperature that separates the top 7% from the bottom 93%. 6. In a sample of 49 adolescents who served as the subjects in an immunologic study, one variable of interest was the diameter of skin

    Confidence Interval Statistics Claims

    1) a statistian claims that the average score on a test of students for students who major in psychology is greater than that of students who major in math results given to 50 students in each group are shown here Is there enough evidence to support the statisticians claim at @=0.01 Show work. Physc Math X1=118