The mayor of Syracuse receives a large number of complaints about excessive speeding on a segment of Highway 81 where the speed limit is 45mph. He decides to undertake a vigorous advertisement campaign that promotes driving within the speed limit. After the campaign has concluded, the city randomly selects a random sample of 50 cars and measures their speed. The mean of the sample is 51mph, with a standard deviation of
25. Solve all two (A and B) .
A) What is the standard error of the mean?
B) What is the 95% confidence interval of the sample mean? Interpret what it tells us.