The head of public safety notices that the average driving speed at a particular intersection averages 35 mph with a standard deviation of 7.5 mph. after a school speed limit sign of 20 mph is placed at the intersection, the first 40 cars travel past at an average speed of 32 mph. using the .01 significance level, was there a significant change in driving speed? solve using the 5 steps of hypothesis testing. also, figure the confidence limits for the 99% confidence interval.
the basic procedure to conduct a hypothesis test
1. formulating hypotheses for the problem
2. evaluating statistic value
3. decision making using a critical value approach
4. decision making using p-value approach
5. arrive at a conclusion