Salaries of 34 college graduates who took a statistics course in college have a mean, x, of $67,400. Assuming a standard deviation, o, of $15,845, construct a 90% confidence interval for estimating the population mean u.

In a test of the effectiveness of garlic for lowering cholesterol, 81 subjects were treated with raw garlic. Cholesterol levels were measured before and after the treatment. The changes (before minus after) in their levels of LDL cholesterol (in mg/dL) have a mean of 0.9 and a standard deviation of 21.5. Use a 0.10 significanc level to test the claim that with garlic treatment, the mean change in LDL cholesterol is greater than 0. What do the results suggest about the effectiveness of the gar treatment? Assume that a simple random sample has been selected. Identify the null and alternative hypotheses, test statistic, P-value, and state the final conclusion that addresses the original claim.

Salaries for an large engineering company are normally distributed with a mean of $80,000 and a standard deviation of $8,450. An employee was having their annual appraisal and the manager indicated that the employee salary for next year has a Z-score of 1.24. Approximately how much will this employee be paid next year in salary? Salary=$[salary] Enter your answer to the nearest hundred of dollars, i.e 50,185 would be entered 50,200.

Suppose that water usages in American showers are normally distributed, with an average shower using 16.4 gallons, and a standard deviation of 3.7 gallons. Estimate the percentage of showers that used between 9 and 23.8 gallons more than 27.5 gallons less than 12.7 gallons between 9 and 20.1 gallons

Assume that adults have IQ scores that are normally distributed with a mean of 104.8 and a standard deviation 21.9. Find the first quartile Q1​, which is the IQ score separating the bottom​ 25% from the top​75%

Salaries of 33 college graduates who took a statistic course in college have a mean ,x of $66,800. Assuming a standard deviation of $11,448, construct a 95% confidence interval for estimating the population mean

Entrance exam scores at Cititon University are normally distributed with a mean of 552 and a standard deviation of 29. If scholarships are awarded to the top 10% of scores, what is the minimum score needed to guarantee a scholarship?

Assume that the average time to run a marathon in the population is 278 minutes with a standard deviation of 63 minutes.  Use this information to answer the question In the population, what raw running time is 2.5 standard deviations below the mean?  What is the percentile of this time?

Butt-to-knee length is approximately normally distributed with a mean of 23.1 inches and a standard deviation of 1.2.  Theater seats are designed to be comfortable for as many adults as possible.  If the seats are required to fit the middle 80% of the population, the seat must be comfortable for what butt-to-knee length range?

In a test of the effectiveness of garlic for lowering​ cholesterol, 50 subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes in their levels of LDL cholesterol​ (in mg/dL) have a mean of 3.2 and a standard deviation of 18.5. Complete parts​ (a) and​ (b) below. a) What is the best point estimate of the population mean net change in LDL cholesterol after the garlic​ treatment? b) Construct a 90​% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. What does the confidence interval suggest about the effectiveness of garlic in reducing LDL cholesterol? What is the confidence interval estimate of the population mean μ​?