A study was conducted to determine if a certain treatment has any effect on the amount of metalremoved in a pickling operation. A random sample of100 pieces was immersed in a bath for 24 hours without the treatment, yielding an averageof 12.2 millimeters of metal removed and a sample standard deviation of1.1 millimeters. A second sample of 200 pieces was exposed to thetreatment, followed by the 24-hour immersion in the bath, resulting in an average removal of 9.1 millimeters of metal with a sample standarddeviation of 0.9 millimeter.a)Compute a 95% confidence interval estimate for the difference between the population means.b)Does the treatment appear to reduce the mean amount of metal removed? ExplainAnswer part a) below and part b) explain on your answer sheetNOTATION: (a,b) is equivalent to a< mean1-mean2

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Answered: A study was conducted to determine if a…

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 quality-control manager at a compact fluorescent light bulb (CFL) factory needs to determine whether the mean life of a large shipment of CFLs is equal to 7,508 hours. The population standard deviation is 840 hours. A random sample of 49 light bulbs indicates a sample mean life of 7,328 hours. Let μ be the population mean. Determine the null hypothesis, H0, and the alternative hypothesis, H1.
On the planet of Mercury, 4-year-olds average 3.1 hours a day unsupervised. Most of the unsupervised children live in rural areas, considered safe. Suppose that the standard deviation is 1.3 hours and the amount of time spent alone is normally distributed. We randomly survey one Mercurian 4-year-old living in a rural area. We are interested in the amount of time X the child spends alone per day. (Source: San Jose Mercury News) Round all answers to 4 decimal places where possible. b. Find the probability that the child spends less than 3.3 hours per day unsupervised. c. What percent of the children spend over 5.1 hours per day unsupervised. % (Round to 2 decimal places)d. 77% of all children spend at least how many hours per day unsupervised? hours.
6.10 Males 20 to 29 years old have a mean height of 69.4 inches with a standard deviation of 3.5 inches. Females 20 to 29 years old have a mean height of 64.1 inches with a standard deviation of 3.1 inches. Find the standardized variable for the heights of males. Find the standardized variable for the heights of females. For a 68‐inch‐tall person, find the value of the standardized variable for males. For a 68‐inch‐tall person, find the value of the standardized variable for females. Compare your answer with part (c) and comment.
On the planet of Mercury, 4-year-olds average 2.9 hours a day unsupervised. Most of the unsupervised children live in rural areas, considered safe. Suppose that the standard deviation is 1.4 hours and the amount of time spent alone is normally distributed. We randomly survey one Mercurian 4-year-old living in a rural area. We are interested in the amount of time X the child spends alone per day. (Source: San Jose Mercury News) Round all answers to 4 decimal places where possible.a. What is the distribution of X? X ~ N(_______ ,______) I know that question a is (2.9,1.4) b. Find the probability that the child spends less than 1.3 hours per day unsupervised. c. What percent of the children spend over 3.4 hours per day unsupervised. % (Round to 2 decimal places) d. 82% of all children spend at least how many hours per day unsupervised? hours. Please help me understand how to do the rest.
A magazine conducts an annual survey in which readers rate their favorite cruise ship. All ships are rated on a 100-point scale, with higher values indicating better service. A sample of 38 ships that carry fewer than 500 passengers resulted in an average rating of 85.62, and a sample of 44 ships that carry 500 or more passengers provided an average rating of 81.10. Assume that the population standard deviation is 4.55 for ships that carry fewer than 500 passengers and 3.97 for ships that carry 500 or more passengers. (a) What is the point estimate of the difference between the population mean rating for ships that carry fewer than 500 passengers and the population mean rating for ships that carry 500 or more passengers? (Use smaller cruise ships − larger cruise ships.) (b) At 95% confidence, what is the margin of error? (Round your answer to two decimal places.) (c) What is a 95% confidence interval estimate of the difference between the population mean ratings for the…
On the planet of Mercury, 4-year-olds average 3.1 hours a day unsupervised. Most of the unsupervised children live in rural areas, considered safe. Suppose that the standard deviation is 1.6 hours and the amount of time spent alone is normally distributed. We randomly survey one Mercurian 4-year-old living in a rural area. We are interested in the amount of time X the child spends alone per day. (Source: San Jose Mercury News) Round all answers to 4 decimal places where possible.b. Find the probability that the child spends less than 1.7 hours per day unsupervised. c. What percent of the children spend over 3.7 hours per day unsupervised. % (Round to 2 decimal places)d. 74% of all children spend at least how many hours per day unsupervised? hours.
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On the planet of Mercury, 4-year-olds average 3.2 hours a day unsupervised. Most of the unsupervised children live in rural areas, considered safe. Suppose that the standard deviation is 1.7 hours and the amount of time spent alone is normally distributed. We randomly survey one Mercurian 4-year-old living in a rural area. We are interested in the amount of time X the child spends alone per day. (Source: San Jose Mercury News) Round all answers to 4 decimal places if not otherwise specified.c. What percent of the children spend over 4.6 hours per day unsupervised. % (Round to 2 decimal places) d. 84.85% of all children spend at least how many hours per day unsupervised? hours. (Round to 2 decimal places)
On the planet of Mercury, 4-year-olds average 3.2 hours a day unsupervised. Most of the unsupervised children live in rural areas, considered safe. Suppose that the standard deviation is 1.3 hours and the amount of time spent alone is normally distributed. We randomly survey one Mercurian 4-year-old living in a rural area. We are interested in the amount of time X the child spends alone per day. (Source: San Jose Mercury News) Round all answers to 4 decimal places where possible.a. What is the distribution of X? X ~ N(,)b. Find the probability that the child spends less than 1.9 hours per day unsupervised. c. What percent of the children spend over 5.2 hours per day unsupervised. % (Round to 2 decimal places)d. 88% of all children spend at least how many hours per day unsupervised? hours.
On the planet of Mercury, 4-year-olds average 3.1 hours a day unsupervised. Most of the unsupervised children live in rural areas, considered safe. Suppose that the standard deviation is 1.6 hours and the amount of time spent alone is normally distributed. We randomly survey one Mercurian 4-year-old living in a rural area. We are interested in the amount of time X the child spends alone per day. (Source: San Jose Mercury News) Round all answers to 4 decimal places where possible.a. What is the distribution of X? X ~ N(,) b. Find the probability that the child spends less than 1.7 hours per day unsupervised. c. What percent of the children spend over 2.3 hours per day unsupervised. % (Round to 2 decimal places) d. 67% of all children spend at least how many hours per day unsupervised?
In a study on the physical activity of young adults, pediatric researchers measured overall physical activity as the total number of registered movements (counts) over a period of time and then computed the number of counts per minute (cpm) for each subject. The study revealed that the overall physical activity of obese young adults has a mean of μ = 325 cpm and a standard deviation of a = 90 cpm. In a random sample of n = 100 obese young adults, consider the sample mean counts per minute, x. Click the icon to view the table of normal curve areas. a. Describe the sampling distribution of x. Find μ. Find o-. X 0-= (Type an integer or a decimal.) Describe the shape of the sampling distribution of x. ✩ OA. Skewed right OB. Approximately normal OC. Skewed left b. What is the probability that the mean overall physical activity level of the sample is between 300 and 310 cpm? P(300 ≤x≤310) = (Round to four decimal places as needed.) c. What is the probability that the mean overall physical…

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