A light bulb manufacturer wants to compare the mean lifetimes of two of its light bulbs, model A and model B. Independent random samples of the two modelswere taken. Analysis of 15 bulbs of model A showed a mean lifetime of 1352 hours and a standard deviation of 88 hours. Analysis of 14 bulbs of model Bshowed a mean lifetime of 1365 hours and a standard deviation of 99 hours. Assume that the populations of lifetimes for each model are normally distributedand that the variances of these populations are equal. Construct a 95% confidence interval for the difference H₁ H₂ between the mean lifetime μ, of model Abulbs and the mean lifetime ₂ of model B bulbs. 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 responses to at least two decimal places. (If necessary, consult a list offormulas.)Lower limit:Upper limit:X5

Analysis of 15 bulbs of model A showed a mean 1352 and standard deviation 88 hours n1=15x1=1352s1=88…

Answered: A light bulb manufacturer wants to…

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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A manufacturer of TV tubes has for many years used a process giving a meantube life of 4700 hours and a standard deviation of 1460 hours. A new process is tried to see if it will increase the life significantly. A sample of 100new tubes gave a mean life of 5000 hours. Is the new process better than the old one at a 1% level of significance?
A laboratory claims that the mean sodium level, μ , of a healthy adult is 141 mEq per liter of blood. To test this claim, a random sample of 80 adult patients is evaluated. The mean sodium level for the sample is 142 mEq per liter of blood. It is known that the population standard deviation of adult sodium levels is 11 mEq. Can we conclude, at the 0.05 level of significance, that the population mean adult sodium level differs from that claimed by the laboratory? Perform a two-tailed test. Then fill in the table below. Carry your intermediate computations to at least three decimal places, and round your responses as specified in the table. The null hypothesis: H0: The alternative hypothesis: H1: The type of test statistic: (Choose one)ZtChi squareF The value of the test statistic:(Round to at least three decimal places.) The two critical values at the 0.05 level of significance:(Round to at least…
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Q17. A medical study found a negative relationship between exercise [in minutes per week] and stress-related health problems [r = -.26]. Answer the questions below. \textit{Hint}Hint: See Q16. 17a. Which of the following conclusions is appropriate? a. Of the variance in stress-related health problems, 6.76% can be explained by the amount of weekly exercise. b. Increasing the amount of exercise per week will cause stress-related health problems to decrease. 17b. Explain why the other is not appropriate. a. The correlation is negative, so we can conclude that it is the exercise that is causing the reduction in stress-related health problems, and not that a reduction in stress-related health problems will increase exercise. b. That variations in exercise account for 6.76% of the variance in stress-related health problems is cause for celebration. c. Correlations do not demonstrate causation
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A researcher collected sample data for 19 middle-aged women. The sample had a mean serum cholesterol level (measured in milligrams per one hundred milliliters) of 190.3, with a standard deviation of 9.5. Assuming that serum cholesterol levels for middle-aged women are normally distributed, find a 95% confidence interval for the mean serum cholesterol level of all women in this age group. Give 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 one decimal place. (If necessary, consult a list of formulas.) Lower limit= Upper limit=
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A researcher collected sample data for 19 middle-aged women. The sample had a mean serum cholesterol level (measured in milligrams per one hundred milliliters) of 191.5, with a standard deviation of 6.5. Assuming that serum cholesterol levels for middle-aged women are normally distributed, find a 95% confidence interval for the mean serum cholesterol level of all women in this age group. Give 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 one decimal place. lower limit ____ Upper Limit ____
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