Use a t-distribution to find a confidence interval for the difference in means μd=μ1-μ2 using the relevant sample results from paired data. Assume the results come from random samples from populations that are approximately normally distributed, and that differences are computed using d=x1-x2. A 95% confidence interval for μd using the paired difference sample results x¯d=2.2, sd=2.2, nd=30. Give the best estimate for μd, the margin of error, and the confidence interval. Enter the exact answer for the best estimate, and round your answers for the margin of error and the confidence interval to two decimal places.   Best estimate = _______ Margin of error = _________ The 95% confidence interval is _______ to _______

A sample of 66 night-school students' ages is obtained in order to estimate the mean age of night-school students. x = 24.7 years. The population variance is 18. (a) Give a point estimate for u. (Give your answer correct to one decimal place.) (b) Find the 95% confidence interval for u. (Give your answer correct to two decimal places.) Lower Limit Upper Limit (c) Find the 99% confidence interval for u. (Give your answer correct to two decimal places.) Lower Limit Upper Limit

A researcher collected sample data for 19 middle-aged women. The sample had a mean serum cholesterol level (measured in milligrams per one hundred milliliters) of 190.3, with a standard deviation of 9.5. Assuming that serum cholesterol levels for middle-aged women are normally distributed, find a 95% confidence interval for the mean serum cholesterol level of all women in this age group. Give the lower limit and upper limit of the 95% confidence interval. Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult a list of formulas.) Lower limit= Upper limit=

In the country of United States of Heightlandia, the height measurements of ten-year-old children are approximately normally distributed with a mean of 55.9 inches, and standard deviation of 4.2 inches.A) What is the probability that a randomly chosen child has a height of less than 59.4 inches?

A sample of 20 automobiles has a pollution by-product release standard deviation of 2.5 ounces when one gallon of gasoline is used. Find the 95% confidence interval of the population variance. using chi table determine the confidence interval of the true population variance

The level of lead in the blood was determined for a sample of 152 male hazardous-waste workers age 20-30 and also for a sample of 86 female workers, resulting in a mean + standard error of 5.3 ± 0.3 for the men and 3.6 t 0.2 for the women. Calculate an estimate of the difference between true average blood lead levels for male and female workers in a way that provides information about reliability and precision. (Use a 95% confidence interval. Round your answers to two decimal places.) Interpret the interval. O we are 95% confident that the true average blood lead level for male workers is less than that of female workers by an amount within the confidence interval. O we are 95% confident that the true average blood lead level for male workers is greater than that of female workers by an amount outside the confidence interval. O we cannot draw a conclusion from the given information. O we are 95% confident that the true average blood lead level for male workers is greater than that of…

A warehouse owner wants to know the average weight of books at his facility. He weighs 18 books and finds that the sample has a mean weight of 9.41 pounds and standard deviation of 2.89 pounds. Construct a 99%confidence interval for the population mean of book weights. Assume the population is normally distributed.Choose the correct confidence interval and critical value used in the calculation. (7.46,11.36)(tc=2.8609) (7.83,10.99)(Zc=2.326) (7.44,11.38) (tc=2.8982) (7.45,11.37) (tc=2.8784) (7.66,11.16)(Zc=2.576)