A study conducted to examine the age of commercial jets in the United States sampled 36 planes and found the average age to be 12.6 years with a standard deviation of 2.7 a. Calculate and interpret a 90% confidence interval for the average age of commercial jets in the United States. b. A report in USA Today claimed that the mean age of commercial jets in the United States was 14 years. Using the confidence interval in (a), is there enough evidence to refute this claim?

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A: Given data,n=352x=18.4s=6.8α=0.05df=n-1=351t-critical value is tc=1.967

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Q: In a study investigating the average salaries of employees in a company, 36 employees of the company…

A: Solution: Given information: n=36 Sample size  x=2400  Sample mean s= 1200 Sample standard deviation…

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Q: In a random sample of seven cell​ phones, the mean full retail price was ​$407.00 and the standard…

A: Solution: Let X bet the retail price of cell phone. From the given information, x-bar=$407, s=$196…

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A: Solution

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Q: A random sample of 40 adults with no children under the age of 18 years results in a mean daily…

A: Given, A random sample of 40 adults with no children under the age of 18 years results in a mean…

Q: A weekly tabloid reported that the average income of its subscribers is $39,100. Assume this…

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Q: An analyst is planning to estimate the mean of a quantitative variable using a 95% confidence…

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Q: In one town, monthly incomes for men with college degrees are found to have a standard deviation of…

A: Given that ,        n=22        standard deviation S=$ 901

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Q: A random sample of 40 adults with no children under the age of 18 years results in a mean daily…

A: Given       n1=40 ; x1=5.03 ; σ1=2.46     n2=40 ; x2=4.48 ; σ2=1.52At 90 ; CI , the t is…

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Q: A random sample of 4040 adults with no children under the age of 18 years results in a mean daily…

A: Given:n1=40, x1=5.13, s1=2.46n2=40, x2=4.25, s2=1.71…

Q: In a random sample of ten ​people, the mean driving distance to work was 23.2 miles and the standard…

A: Provided information is ; Sample size(n) =10  Mean(μ) = 23.2 Sample standard deviation(s) = 5.3…

Q: In a survey to estimate the mean time spent by office workers per day checking for and sending out…

A: From the provided information, Sample size (n) = 30 Sample mean (x̅) = 2 hours or 120 minutes…

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A: Determine the confidence interval for the considered mean time by using the formula: 95% Confidence…

Q: In a random sample of twelve ​people, the mean driving distance to work was 18.8 miles and the…

A: From the given information we want to construct 90% confidence interval.

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Q: The national fire protection association reported that house fires in the United States result in…

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Q: A manufacturer of electronics will not accept a shipment of parts from a vendor if there is reason…

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A: The provided information are:

Q: In a random sample of ten cell phones, the mean full retail price was $554.00 and the standard…

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A: Given : n= 38.0 , x= 67.0 s= 11.0 At 95.0 % confidence level , z score= 1.96

Q: 2. A sample of seven college wrestlers had an average weight of 267 pounds with a sample standard…

A: Given that  Sample size (n)=7  Sample mean = 267  Sample standard deviation (s)= 10  We have to find…

Q: Statewide, social workers average 10.2 years of experience. In a random sample, 203 social workers…

A: Given information: μ=10.2, x=8.7, s=0.52, n = 203 Determine the null hypothesis and an alternative…

Q: In a particular community, it is claimed that the mean household water usage for a particular month…

A: Hypothesis testing is conducted for the parameters of the population like population mean,…

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