A college has decided to add support courses to its statistics classes to assist students. Welook at the next semester to determine if the addition of the support courses assistedstudents. In a sample of 4 courses with support courses the average final grade of 160students was 78% with a standard deviation of 2%. Calculate a 95% confidence interval forthe population mean of students who took a support course. (Type numbers in Excelcalculator without percent sign)O (77.69, 78.31)O (77.70, 78.30)O (77.69, 78. 30)O (77.68, 78.31)4 is not larger than 40 so we cannot compute a confidence interval.

Confidence interval give a range of values for the unknown parameter of the population. The width of…

Answered: A college has decided to add support…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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The Ball Corporation’s beverage can manufacturing plant in Fort Atkinson, Wisconsin, uses a metal supplier that provides metal with a known thickness standard deviation σ 5 .000959 mm. If a random sample of 58 sheets of metal resulted in x− 5 0.2731 mm, calculate the 99 percent confidence interval for the true mean metal thickness.
A manufacturer of sprinkler systems used for fire protection in office buildings claims that the true average system-activation temperature is 130 . A sample of n=9 systems, when tested, yields a sample average activation temperature of 131.08 F with a standard deviation 1.5F. Suppose the distribution of activation times is normally distributed. Is there sufficient evidence to believe that the average activation temperature of the sprinklers is different from manufacturer claims? (Use 5% significance level)? If you calculate a 95% confidence interval, will 130 be inside or outside the interval? Explain your answer without calculating the interval.
In a current study, a random sample of 10 teachers from Texas and an independent random sample of 10 teachers from Virginia have been asked to report their annual income. The data obtained are as follows. (See attachment for data table and full question). The population standard deviations for the annual incomes of teachers in Texas and in Virginia are estimated as $6100 and $6600, respectively. It is also known that both populations are approximately normally distributed. Construct a 95% confidence interval for the difference −μ1μ2 between the mean annual income of teachers from Texas (μ1) and the mean annual income of teachers from Virginia (μ2). Then find the lower limit and upper limit of the 95% confidence interval. Carry your intermediate computations to at least three decimal places. Round your answers to at least two decimal places. a.) The Lower Limit is: b.) The Upper Limit is:
A trucking fleet-owner owns two semi-trucks and wishes to compare the amount of fuel used per week by the two vehicles. In a random sample of 100 weeks, truck #1 used a mean volume of 340 gallons with a standard deviation of 11 gallons. In a second, independent random sample of 100 weeks, truck #2 used a mean volume of 331 gallons with standard deviation 6 gallons.It is of interest to construct a confidence interval for the difference in population means using a confidence level of 90 percent. ?1−?2, where ?1 is the mean fuel volume used by truck #1 and ?2 is the mean volume of fuel used by truck #2. Note: 340−331=9 and 112100+62100‾‾‾‾‾‾‾‾‾‾‾√=1.25299640861417 Your answers below should be entered as numbers. Do not round during intermediate steps. If you round an answer, make sure you do so correctly and keep at least three decimal places. (a) The estimate is: gallons. (b) The standard error is: gallons. (c) The multiplier is: .
The Ball Corporation's beverage can manufacturing plant in Fort Atkinson, Wisconsin, uses a metal supplier that provides metal with a known thickness standard deviation σ = .000672 mm. Assume a random sample of 56 sheets of metal resulted in an x⎯⎯x¯ = .2737 mm. Calculate the 98 percent confidence interval for the true mean metal thickness. (Round your answers to 4 decimal places.)
The Ball Corporation's beverage can manufacturing plant in Fort Atkinson, Wisconsin, uses a metal supplier that provides metal with a known thickness standard deviation σ = .000652 mm. Assume a random sample of 52 sheets of metal resulted in an x¯x¯ = .3373 mm. Calculate the 95 percent confidence interval for the true mean metal thickness. The 95% confidence interval is from _____ to ______.
The president of an all-female school wants to know if the students at her school studied more or less, on average, than the students at a neighboring all-male school. To find out, she conducted a study. Accordingly, samples were taken at each school with the following results: All female: sample size = 43, mean study time ( hours) = 18.56, standard deviation (hours) = 4.35 All male: sample size = 38, mean study time (hours) =17.95, standard deviation (hours) = 4.87 Calculate the 95% confidence interval for the differences between population means. Use brackets write the final answer [x.xx, x.xx]

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