To assess the accuracy of a laboratory scale, a standard weight known to weigh 1 gram is repeatedly weighed a total of n times, and the mean of the weightings is computed. Suppose the scale readings are Normally distributed, with unknown mean m and standard deviation 0.01 . How large should n be, so that a 95% confidence interval for m has a margin of error of  0.0001?

A sample of size n=49 is drawn from a popular whose standard deviation is q=4.8. a. Find the margin of error for a 95% confidence interval for "u". b. If the sample size were n=60, would the margin of error be larger or smaller?

To compare the dry braking distances from 30 to 0 miles per hour for two makes of​ automobiles, a safety engineer conducts braking tests for 35 models of Make A and 35 models of Make B. The mean braking distance for Make A is 43 feet. Assume the population standard deviation is 4.6 feet. The mean braking distance for Make B is 46 feet. Assume the population standard deviation is 4.5 feet. At α=0.10​, can the engineer support the claim that the mean braking distances are different for the two makes of​ automobiles? Assume the samples are random and​ independent, and the populations are normally distributed.   The critical​ value(s) is/are   Find the standardized test statistic z for μ1−μ2.

If n=27, (x-bar)=46, and s=19, construct a confidence interval at a 99% confidence level. Assume the data came from a normally distributed population. Give your answers to one decimal place. <μ<