An efficiency expert wishes to determine the average time required to drill three holes in a metal component. How large a sample is needed to be 95 percent confident that the sample mean is within 15 seconds of the true mean? Assume it is known from previous studies that σ = 40 sec.
An efficiency expert wishes to determine the average time required to drill three holes in a...
An engineer wishes to determine the average time (in seconds) required to drill holes in some metal flange. Determine the required sample size to be 99% certain that the sample mean will be within 15 seconds of the true average, assuming that the standard deviation of the time is o = 30 seconds. A. 26 B. 27 C. 28 D. 29 E. none of the preceding
An engineer wishes to determine the average time (in seconds) required to drill holes in some metal flange. Determine the required sample size to be 99% certain that the sample mean will be within 15 seconds of the true average, assuming that the standard deviation of the time is o 30 seconds. A. 26 B. 27 C. 28 D. 29 E. none of the preceding
Multiple Choice Question An engineer wishes to determine the average time (in seconds) required to drill holes in some metal flange. Determine the required sample size to be 99% certain that the sample mean will be within 15 seconds of the true average, assuming that the standard deviation of the time is o = 30 seconds. A. 26 B. 27 C. 28 D. 29 E. none of the preceding
Question 13 D 1 pts A university of dean of students wishes to estimate the average number of hours students spend doing homework per week. The standard deviation from a previous study is 6.2 hours. How large a sample must be selected if he wants to be 99% confident of finding whether the true mean differs from the sample mean by 1.5 hours? 1 pts Question 14 If the variance of a national accounting examination is 900, how large a...
9. Suppose that a milk producer wishes to estimate the mean shelf life (in days) of one-gallon cartons of milk. The population standard deviation is known from past studies. If the manufacturer wishes to be 95% confident of getting an estimate within 2 days of the true mean shelf life, what was the standard deviation (0) if the required sample size is 138.3 before rounding up?
Determine the average time (in seconds) required to perform some type of physical labor: What is the required sample size to be 99% certain that the sample mean will be within 15 seconds of the true average, if the standard deviation of the time is σ = 30 seconds?
5. An efficiency expert wants to determine the average amount of time it takes a particular pit crew to change a set of tires on a race car. The expert had the pit crew change a set of tires 10 times, and found that the sample mean of those times is 20 seconds and their sample standard deviation was 12.2 seconds (a) (5 points) State an appropriate interval estimator for the true average amount of time it would take the...
Suppose a university wishes to estimate the average weight of their undergraduate male students. A random sample of 200 undergraduate male students at this university are sampled. It is found that the sample mean weight is 83.3 kg, with a corresponding 95% confidence interval for mu of (81.3, 85.3). Of the following options, which one is the most appropriate interpretation of that interval? We can be 95% confident that the sample mean weight of the 200 undergraduate male students in...
Efficient manufacturing: Efficiency experts study the processes used to manufacture items i order to make them as efficient as possible. One of the steps used to manufacture a metal clamp involves the drilling of three holes. In a sample of 55 clamps, the mean time to complete this step was 50.0 seconds. Assume that the population standard deviation is o = 8 seconds. Part 1 Construct a 99% confidence interval for the mean time needed to complete this step. Round...
3. A random sample of 76 three-year olds attending daycare showed that the yearly tuition average is $5648. Assume the population standard deviation is known to be $630. Find the 98% confidence interval of the mean yearly daycare tuition 4. A researcher is interested in estimating the average monthly salary of sports reporters in a large city. He wants to be 90% confident with his estimate. If the standard deviation is $1500, how large of a sample is needed to...