The production manager of a large manufacturing company estimates that the mean age of his workers is 22.8 years. The treasurer of the firm needs more accurate employees’ average age figure to estimate the cost of an annuity benefit program being considered for employees. The treasurer takes a random sample of 25 employees and finds that the mean age of the sampled employees is 26.2 years with a standard deviation of 4.6 years. At 99% confidence interval, test the hypothesis that the mean age of the employees is not equal to 22.8 years.

Q: Researchers found that in certain counties in the country, females spend an average of 65 days in…

A: standard deviationσ=4n=36x¯=65

Q: The housing market has recovered slowly from the economic crisis of 2008. Recently, in one large…

A: Given Mean=9916 Standard deviations=1085 n=49

Q: A random sample of 21 Camden County College students had a mean age of 24 years, with a standard…

A:

Q: Can you please calculate the 95% confidence interval for this problem

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Q: Suppose that grade point averages of undergraduate students at one university have a bell-shaped…

A: Given, grade point averages of undergraduate students at one university have a bell-shaped…

Q: The Human Resource Department (HRD) of a company developed an aptitude test for screening potential…

A: Solution: Given information: n= 13 Sample size  x=96 Sample meanμ=100 Population means= 5.2 sample…

Q: Determine a 95% confidence interval for the mean, rounding all values to the nearest tenth.

A: Given data  Mean = 512 Standard deviation = 109 Sample size = 51 Confidence level = 95% Alpha = 1-…

Q: Suppose you observe 77 data points from a distribution with standard deviation 8.4, and you…

A: Given that,  σ=8.4,n=77 Critical values: By using the z-table, the critical value at 92% confidence…

Q: 4. Felician University uses hundreds of fluorescent light bulbs each year. The brand of bulb it…

A: The mean lifetime of current brand that it uses is of 900 hours. The mean and standard deviation of…

Q: Testing the hypothesis using a one-tailed test at 0.01 level of significance, do these data support…

A: here  population standard deviation  = 12 n= 36 alpha  =   0.01

Q: You are a researcher for the National Highway Traffic Safety Administ estimate the average blood…

A: Given that,The sample size is The sample mean BAC (Blood Alcohol Concentration) is The known…

Q: A personnel manager has found that, historically, the scores on aptitude tests given to applicants…

A: Given: σ=25.6, n=12 and x=69.86. Now, use upper limit of the confidence interval to find the value…

Q: Find the lower boundary of the 90% confidence interval for the variance of the ages of seniors at…

A: Given information: n=24 s=2.04 Confidence interval for variance: n-1s2χ1-α2,n-12≤σ2≤n-1s2χα2,n-12

Q: A mechanic sells a brand of automobile tire that has a life expectancy that is normally​…

A: Normal distribution is the type of continuous distribution. Here most of the observations centred in…

Q: A sample of 24 randomly selected commuters in Chicago showed the average of the commuting times was…

A:

Q: A researcher collected sample data for 17 women ages 18 standard deviation of 9.3. Assuming that…

A:

Q: A college admissions officer for the school’s online undergraduate program wants to estimate the…

A: The objective of this question is to determine whether the true mean age of online undergraduate…

Q: Find a credible journal article or website where confidence intervals were used to make informed…

A: From the given information we find the solution.

Q: To determine the average number of minutes it takes to manufacture one unit of a new product, an…

A: Given information Sample size (n) = 15 Sample mean x̅ = 3.92 Standard deviation (s) = 0.45 Taking…

Q: The housing market has recovered slowly from the economic crisis of 2008.​ Recently, in one large​…

A: n=42, sample mean x̄=9160, s=1631

Q: You are a researcher studying the lifespan of a certain species of bacteria. A preliminary sample of…

A: Solution: Given data: Preliminary Sample size = 40 Sample mean = 72 Standard deviation  = 6.4 Margin…

Q: A recent study of 26 city residents showed that the time they had lived at their present address has…

A: Given, Sample size = 26 Sample mean = 10.3 Sample standard deviation = 3   Since the population…

Q: sample standard deviation of $74.50. a. Develop a  95% confidence interval estimate of the mean…

A: The sample size, i.e., the sampled number of families, n=64.The sample average spent amount(in $)…

Q: Suppose that grade point averages of undergraduate students at one university have a bell-shaped…

A: According to the given information, we have Mean = 2.55 Standard deviation = 0.43 Given that the…

Q: Suppose that shoe sizes of American women have a bell-shaped distribution with a mean of 8.11 and a…

A: Given that the shoe sizes of American women have a bell-shaped distribution with a mean of 8.11 and…

Q: The housing market recovered slowly from the crisis of 2008. Realtors in one community have recently…

A: The housing market recovered slowly from the crisis of 2008. Realtors in one community have recently…

Q: A researcher is interested in estimating the mean blood alcohol content (BAC) of people arrested for…

A: From the provided information, Sample size (n) = 250 Standard deviation (σ) = 0.065 Confidence level…

Q: A survey conducted by the American Automobile Association (AAA) showed that a family of four spends…

A: Given that: Population mean, μ=215.60 n = 64 x¯=252.45 s = 74.50

Q: The distribution of study times for first-year students follows a normal distribution with a…

A:

Q: In the last quarter of​ 2007, a group of 64 mutual funds had a mean return of 3.4​% with a standard…

A:

Q: The age when smokers first start from previous studies is normally distributed with a mean of 13…

A: Given,sample size(n)=22sample mean(x¯)=13.8standard deviation(σ)=2.1α=1-0.90=0.1α2=0.05Z0.05=1.645…

Q: A mechanic sells a brand of automobile tire that has a life expectancy that is normally distributed,…

A: Given that Mean μ=27000 Standard deviationσ =24000 P(X < a) = 0.1(10%) P(X< a) =…

Q: A mechanic sells a brand of automobile tire that has a life expectancy that is normally​…

A: The mean is 34,000 and the standard deviation is 2400.

Q: An existing inventory for a test measuring self-esteem indicates that the scores have a standard…

A: Mean()=61standard deviation()=12sample size(n)=70confidence level=90%

Q: A shareholders' group is lodging a protest against your company. The shareholders group claimed that…

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Q: A popular weight loss program claims users will lose weight each month. Linda samples 25 dieters and…

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Q: A tech company wants to estimate the average battery life for one of their new line of laptops. In…

A: Obtain the 99% confidence interval for the true average battery life of the laptop: Denote the true…

Q: A personnel manager has found that, historically, the scores on aptitude tests given to applicants…

A:

Q: Students at a major university are complaining of a serious housing crunch. Many of the university’s…

A: A. Suppose X is a random variable with expectation, μ and standard deviation, σ. Then, for any…

Q: company manufactures a certain over-the-counter drug. The company samples 80 pills and finds that…

A: We have given that  Sample size n = 80 Sample mean = 325.5 Standard deviation s=10.3 90%confidence…

Q: The slope of a regression line is 0.8, and the standard error of the slope is 0.3. The sample used…

A:

Q: (3) A researcher is interested in estimating the average age when cigarette smokers first began to…

A: Here n = 350, Sample mean = x-bar = 16.8, Sample SD = s = 1.8 years Now since sample size is very…