The Ball Corporation's beverage can manufacturing plant in Fort Atkinson, Wisconsin, uses a metal supplier that provides metal with a known thickness standard deviation σ = .000619 mm. Assume a random sample of 46 sheets of metal resulted in an x¯x¯ = .1903 mm.   Calculate the 99 percent confidence interval for the true mean metal thickness. (Round your answers to 4 decimal places.)    The 99% confidence interval is from   to

A statistics class is estimating the mean height of all female students at their college. They collect a random sample of 42 female students and measure their heights. The mean of the sample is 65.3 inches and the sample standard deviation is 5.4 inches. Find the 90% confidence interval for the mean height of all female students in their school? Assume that the distribution of individual female heights at this school is approximately normal. 1. The t value is 1.3025 2. The standard error has a value of -- 3. The margin of error has a value of 4. Find the 90% confidence interval for the mean height of all female students in their school

You measure 40 randomly selected textbooks' weights, and find they have a mean weight of 78 ounces. Assume the population standard deviation is 6.4 ounces. Based on this, construct a 90% confidence interval for the true population mean textbook weight. Give your answers as decimals, to two places εμε

A simple random sample with n = 52 provided a sample mean of 24.0 and a sample standard deviation of 4.6. a. Develop a 90% confidence interval for the population mean (to 1 decimal). b. Develop a 95% confidence interval for the population mean (to 1 decimal). c. Develop a 99% confidence interval for the population mean (to 1 decimal). d. What happens to the margin of error and the confidence interval as the confidence level is increased? V - Select your answer - They increase They decrease They stay the same It cannot be determined from the given data The margin of error increases and the confidence interval becomes narrower The margin of error decreases and the confidence interval becomes wider

Suppose the heights of a population of men are normally distributed with an unknown population mean and a population standard deviation of 2.4  inches. A random sample of men from the population produces a sample mean  height of x ¯ =68.2  inches. What value of z  should be used to calculate a confidence interval with a 90%  confidence level? z 0.10   z 0.05   z 0.025   z 0.01   z 0.005   1.282  1.645  1.960  2.326  2.576

A researcher believes that the mean of a population is 45.2. She collects data from a sample (n = 81) and finds that the sample mean is 40.4, with a standard deviation of 19. Construct a 90% confidence interval to determine whether 45.2 is a reasonable hypothesis about the value of mu.