The mean replacement time for a random sample of 20 washing machines is 10.9 years and the standard deviation is 2.7 years. Construct a 99% confidence interval for the standard deviation, σ, of the replacement times of all washing machines of this type

Q: Find a 95% confidence interval for the sample mean of Y = X̄12 + X̄22 when X̄'s are obtained from…

A: Given X¯'s are obtained from standard normal population.

Q: mple of 400 items is found to have mean of 82 and standard deviation is 18. Find 95% confidence…

A: Given: Sample mean x¯=82     Sample standard deviation (s) = 18 Sample size (n) = 400 Confidence…

Q: Find a 90% confidence interval for the population mean, if the sample size is 58, the sample mean is…

A:

Q: A random sample of 94 lightbulbs have a mean life of x=587 hours with a standard deviation of 36…

A: According to the provided information, Point estimate = sample mean =  = 587 sample standard…

Q: The mean replacement time for a random sample of 12 microwave ovens is 8.6 years with a standard…

A: Given: n=12, x=8.6, s=3.6 and 1-α=95%. Then,α=1-95%=1-0.95=0.05 Also,The degree of…

Q: Presented are the ozone concentrations in areas of Philippines, Japan, Taiwan, and Singapore. Obtain…

A: Given  the ozone concentrations in areas of Philippines, Japan, Taiwan, and Singapore.

Q: use this to find a 95% confidence interval for the mean height of all red maple trees

A: The sample size is n = 146 Sample mean = 59 And sample SD = 12 Since the sample size is large then…

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A:

Q: Find a 90% confidence interval for the mean of a normal distribution if population variance is 4 and…

A: Given CL = 0.90 Population variance, σ2=4 Sample size, n=8 9,14,10,12,7,13,11,12

Q: The mean replacement time for a random sample of 12 cd players is 8.6 years with a standard…

A:

Q: The lifetime of a certain brand of battery is known to have a standard deviation of 19.8  hours.…

A: Given Information: Standard deviation (σ) = 19.8 Sample size (n) = 150 Sample mean (x¯) = 34   To…

Q: An economics professor randomly selected 100 millionaires in the United States.  The average age of…

A: According to the provide information,

Q: Construct a 95% confidence interval for the population variance σ² if a sample of size 25 has…

A:

Q: The mean score of a random sample of 22 students’ applicants who took the college entrance…

A: Given :    Sample size (n) =22

Q: A researcher takes a sample of 25 people and calculates a 90% confidence interval of (4,24) for a…

A: The confidence interval is (4,24).

Q: 95% confidence interval for the average increase of height.

A: Given that  In year 1970 In year 2020 Mean (μ1)=30  Mean (μ2) = 31.5  Variance (σ12) = 4.5…

Q: A random sample of 5 months in an urban area showed an average of 28 mail carriers were bitten by…

A: Here we need to construct a 95% confidence interval for the mean number of mail carriers who were…

Q: Find a 99% confidence interval for the mean of weights of Siamese cats if the population standard…

A: We have given that Sample mean (x̄) = 11.8, population standard deviation (σ) = 2.1 and sample size…

Q: 20 TV remote controls were followed over the years to find the mean lifespan of this model. The…

A: Answer - Here  n = 20 TV remote controls were followed  over the years to find the mean…

Q: Suppose average pizza delivery times are normally distributed with an unknown population mean and a…

A: The provided information is:

Q: A sample of 28 elements is selected to estimate a 95% confidence interval for the variance of the…

A: We have given that  sample size=n=28 95% confidence interval for variance

Q: A random of 15 freshmen takers obtained a mean score of 74 and a variance of 9 on a SASE. Assuming…

A: Given,sample size(n)=15standard deviation(s)=9=3degrees of…

Q: Construct a 95% confidence interval for the population standard deviation σ if a sample of size 10…

A: Solution

Q: Find the 95% confidence interval for the variance and standard deviation of the heights of maple…

A: Construct the 95% confidence interval for the variance. Obtain the critical values. The standard…

Q: The lifetime of a certain brand of battery is known to have a standard deviation of  19.8  hours.…

A: Let, X: Life time of a battery Given, Sample (n) = 80 Known standard deviation (sd) is 19.8…

Q: An agricultural researcher plants 14 plots with a new variety of corn. The average yield for these…

A: Given data: Sample size  =14 Sample mean = 155 Sample standard deviation  = 10 Confidence level = 90…

Q: A random sample of 15 employees was selected. The average age in the sample was 31 years with a…

A: It is given that, Sample mean = 31 years. Sample variance is 49 years, that is, sample standard…

Q: A random sample of 9 observations from a normally distributed population produced a mean x̅ =12.4…

A: Given information Sample size(n) = 9 Sample mean x̅ = 12.4 Sample standard deviation = 2.8…

Q: An electrical firm manufactures T.V. picture tubes that have a length of life that is approximately…

A:

Q: A random sample of 42 KU college students gave a mean age of their vehicles of 11.3 years and a…

A: Let U1 denotes the age of the vehicles of 42 KU college students. Let U2 denotes the age of the…