In: Statistics and Probability
Determine an approximate sample size required to construct a 90% confidence interval for the mean number of miles on four-year -old Honda Civics, with a margin of error of 1000 miles. Assume that a preliminary study showed that the standard deviation is estimated to be 19,700 miles.
A random sample of 32 washing machines had a mean replacement time of 10.6 years and a population standard deviation of 2.1 years. Find the margin of error that corresponds to 99% confidence level.
A football coach randomly selected ten players and timed below long each player took to perform a certain drill. The times (in minutes) were:
7.6 10.4 9.7 8.4 11.8
7.0 6.5 11.1 10.4 12.4
Construct a 95% confidence interval for the mean time for all players