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 models were taken. Analysis of 13 bulbs of modelA showed a mean lifetime of 1358 hours and a standard deviation of 105 hours. Analysis of 12 bulbs of model B showed a mean lifetime of 1357 hours and a standard deviation of 103 hours. Assume that the populations of lifetimes for each model are normally distributed and that the variances of these populations are equal. Construct a 90% confidence interval for the difference u,-, between the mean lifetime u, of model A bulbs and the mean lifetime u, of model B bulbs. Then find the lower limit and upper limit of the 90% 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 of formulas.) Lower limit: Upper limit:
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 models were taken. Analysis of 13 bulbs of modelA showed a mean lifetime of 1358 hours and a standard deviation of 105 hours. Analysis of 12 bulbs of model B showed a mean lifetime of 1357 hours and a standard deviation of 103 hours. Assume that the populations of lifetimes for each model are normally distributed and that the variances of these populations are equal. Construct a 90% confidence interval for the difference u,-, between the mean lifetime u, of model A bulbs and the mean lifetime u, of model B bulbs. Then find the lower limit and upper limit of the 90% 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 of formulas.) Lower limit: Upper limit:
Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
18th Edition
ISBN:9780079039897
Author:Carter
Publisher:Carter
Chapter10: Statistics
Section10.5: Comparing Sets Of Data
Problem 14PPS
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Transcribed Image Text: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 models
were taken. Analysis of 13 bulbs of model A showed a mean lifetime of 1358 hours and a standard deviation of 105 hours. Analysis of 12 bulbs of model B
showed a mean lifetime of 1357 hours and a standard deviation of 103 hours. Assume that the populations of lifetimes for each model are normally distributed
and that the variances of these populations are equal. Construct a 90% confidence interval for the difference µ, –, between the mean lifetime lj of model A
bulbs and the mean lifetime µ, of model B bulbs. Then find the lower limit and upper limit of the 90% 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 of
formulas.)
Lower limit:||
Upper limit:I
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