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 12 bulbs of model A showed a mean lifetime of 1372 hours and a standard deviation of 115 hours. Analysis of 14 bulbs of model Bshowed a mean lifetime of 1394 hours and a standard deviation of 92 hours. Assume that the populations of lifetimes for each model are normally distributedand that the variances of these populations are equal. Construct a 90% confidence interval for the difference ₁-₂ between the mean lifetime ₁ of model Abulbs and the mean lifetime μ₂ 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 offormulas.)Lower limit:Upper limit:S?ASubmit Assignment

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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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The fan blades on commercial jet engines must be replaced when wear on these parts indicates too much variability to pass inspection. If a single fan blade broke during operation, it could severely endanger a flight. A large engine contains thousands of fan blades, and safety regulations require that variability measurements on the population of all blades not exceed ?2 = 0.18 mm2. An engine inspector took a random sample of 81 fan blades from an engine. She measured each blade and found a sample variance of 0.28 mm2. Using a 0.01 level of significance, is the inspector justified in claiming that all the engine fan blades must be replaced? (b) Find the value of the chi-square statistic for the sample. (Round your answer to two decimal places.) Find or estimate the P-value of the sample test statistic. P-value > 0.1000.050 < P-value < 0.100 0.025 < P-value < 0.0500.010 < P-value < 0.0250.005 < P-value < 0.010P-value < 0.00 Find a 90% confidence interval…
A study was conducted using 50 mobile network users who volunteered to participate in a research as the entry of the third telco player in the country is on its way. One of the variables studied was the data connection speed in the previous month. Based on the data in the following table, is there a significant difference between the connectivity speeds of the two present mobile networks during the previous month? Use a 5% level of significance and assume that the population variances are equal. 1. The alternative hypothesis for the test would be? 2. The alternative hypothesis for the test would be? 3. What is the computed value of the test statistic? 4. What would be your decision?
The mean age of 31 slot mechanic player is 51.3 years, and the standard deviation is 6.8 years.the mean age of a different sample of 35 roulette player is 54.8 year and standard deviation is 3.2 years. Can it be concluded at alpha = 0.01 that the mean age of slot machine players is less than those players roulette? Assume the variance are equal Step 1= Step 2= Step 3= Step 4=
In a research setting, the efficiency of homecare workers (part-time and full-time) were compared. Data is given below. Is there a difference between full-time and part-time homecare workers? (Variances are assumed to be homogenous, α=0.05). Group Efficiency Points Group Efficiency Points Full-time 5 Part-time 1 Full-time 3 Part-time 3 Full-time 4 Part-time 4 Full-time 1 Part-time 4 Full-time 2 Part-time 2 Full-time 3 Part-time 0 Full-time 2
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 10 bulbs of model A showed a mean lifetime of 1347 hours and a standard deviation of 92 hours. Analysis of 13 bulbs of model B showed a mean lifetime of 1380 hours and a standard deviation of 111 hours. Assume that the populations of lifetimes for each model are normally distributed and that the variances of these populations are equal. Construct a 95% confidence interval for the difference −μ1μ2 between the mean lifetime μ1 of model A bulbs and the mean lifetime μ2 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. Upper Limit Lower Limit:
The variability in the amounts of impurities present in a batch of chemical used for a particular process depends on the length of time the process is in operation. A manufacturer using two production lines, 1 and 2, has made a slight adjustment to line 2, hoping to reduce the variability as well as the average amount of impurities in the chemical. Samples of 25 and 25 measurements from the two batches yield 1.04, respectively 0.51 variances. Do the data present sufficient evidence to indicate that the process variability is less for line 2? Use 5% significance level. Conduct a hypothesis test of the airline executive’s belief. [α = 0.05]
Give a 99.8% confidence interval, for μ₁ −μ₂ given the following information. n₁ = 35, x₁ = 1 2.41, s₁ = 0.39 81 n₂ = 20, x₂ = 2.62, s₂ = 0.83 2 -0.21 ✓0.69 X Use Technology Rounded to 2 decimal places.
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A certain producer of chocolate has some problems with the variability of five suppliers of cocoa. Since the cocoa quality is critical to the final chocolate product, the company has decided to perform a DOE to compare these suppliers. According to experiences with customers, the capacity of detection of any variation is 3.5 units. Estimate the sample size needed to get at least a power of 85%, given that the historical variance of the process is 2.5 units.
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One study claims that the variance in the resting heart rates of smokers is different than the variance in the resting heart rates of nonsmokers. A medical student decides to test this claim. The sample variance of resting heart rates, measured in beats per minute, for a random sample of 9 smokers is 480.7. The sample variance for a random sample of 9 nonsmokers is 131.6. Assume that both population distributions are approximately normal and test the study’s claim using a 0.10 level of significance. Does the evidence support the study’s claim? Let smokers be Population 1 and let nonsmokers be Population 2. Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. H0: σ21=σ22: Ha: σ21⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯σ22 Step 2 of 3: Compute the value of the test statistic. Round your answer to four decimal places. Step 3 of 3: Draw a conclusion and interpret the decision.
chester butchery supplies vienna sausages in the entire kzn province. a meat packer is investigating the marked mass shown on vienna sausages. a pilot study showed a mean of 11.8kg per pack and a variance of 0.49kg. how many packs should be sampled in order to be 92% confident that the sample mean will differ by at most 0.2kg.

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