The lifespan of a 100-W fluorescent lamp is define to be normally distributed with ơ = 30 hrs. A random sample of 15 lamps has a mean life of X = 1000 hours. Construct a 95% lower-confidence bound on the mean life. OHZ 987 1001 SH 1002 SH 990 SH HZ 1002 1007 SH Ομ2 007 HZ 984 Ou2 1001 984 sH O HZ 990 987 SH

The lifespan of a 100-W fluorescent lamp is define to be normally distributed with ơ = 30 hrs. A random sample of 15 lamps has a mean life of X = 1000 hours. Construct a 95% lower-confidence bound on the mean life. OHZ 987 1001 SH 1002 SH 990 SH HZ 1002 1007 SH Ομ2 007 HZ 984 Ou2 1001 984 sH O HZ 990 987 SH

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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A random sample of 76 eighth-grade students' scores on a national mathematics assessment test has a mean score of 273. This test result prompts a state school administrator to declare that the mean score for the state's eighth graders on this exam is more than 270. Assume that the population standard deviation is 33. At α=0.02, is there enough evidence to support the administrator's claim? Complete parts (a) through (e). Part 1 (a) Write the claim mathematically and identify H0 and Ha. Choose the correct answer below. A.) H0: μ≥270 (claim) Ha: μ<270 B.) H0: μ≤270 (claim) Ha: μ>270 C.) H0: μ=270 (claim) Ha: μ>270 D.) H0:μ≤270 Ha: μ>270 (claim) E.) H0: μ<270 Ha: μ≥270 (claim) F.) H0: μ=270 Ha: μ>270 (claim) (b) Find the standardized z, and its coresponding area z=_____ (c) Find the P-value P-value =_____ (d) Decide whether to reject or fail the null…
A shipping firm suspects that the mean life of a certain brand of tire used by its trucks is lessthan 38,500 miles. To check the claim, the firm randomly selects and tests 28 of these tires and gets a mean lifetime of 37,550 miles with a standard deviation of 1250 miles. At α = 0.02, test the shipping firm's claim. Round the test statistic to the nearest thousandth.
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The lifetime of a particular component is normally distributed with a mean of 1000 hours and a standard deviation of 100 hours. What is the 80th percentile of component lifetimes?
Currently patrons at the library speak at an average of 61 decibels. Will this average increase after the installation of a new computer plug in station? After the plug in station was built, the librarian randomly recorded 57 people speaking at the library. Their average decibel level was 63.8 and their standard deviation was 9. What can be concluded at the the αα = 0.10 level of significance?
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Assume that the weights of trout in a river are normally distributed. You randomly catch and weigh 20 such trout. The mean weight from your sample is 7.3 lb with a standard deviation of 0.9 lb. Test the claim that the mean weight of trout in this river is greater than 7 lb at a significance level of 0.01. Be sure to clearly identify your work, using appropriate notation at each step of the process, and summarize your final result in a complete sentence.
A company manufactures tennis balls. When its tennis balls are dropped onto a concrete surface from a height of 100 inches, the company wants the mean height the balls bounce upward to be 54.7 inches. This average is maintained by periodically testing random samples of 25 tennis balls. If the t-value falls between - to 99 and to 99, then the company will be satisfied that it is manufacturing acceptable tennis balls. A sample of 25 balls is randomly selected and tested. The mean bounce height of the sample is 56.7 inches and the standard deviation is 0.25 inch. Assume the bounce heights are approximately normally distributed. Is the company making acceptable tennis balls? Find -to 99 and to.99- - to.99 = to.99 = (Round to three decimal places as needed.) Find the t-value. t-value = Is the company making acceptable tennis balls? Choose the correct answer below. O A. The tennis balls are not acceptable because the t-value falls outside -tn og and to oa.
A company manufactures tennis balls. When its tennis balls are dropped onto a concrete surface from a height of 100 inches, the company wants the mean height the bails bounce upward to be 55.4 inches. This average is maintained by periodically testing random samples of 25 tennis balls. If the t-value falls between - to 90 and to so. then the company will be satisfied that it is manufacturing acceptable tennis balls. A sample of 25 balls is randomly selected and tested. The mean bounce height of the sample is 56.2 inches and the standard deviation is 0.25 inch. Assume the bounce heights are approximately normally distributed. Is the company making acceptable tennis balls? Find - to so and to so -o s0 to so O (Round to three decimal places as needed.)
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