A highway construction zone has a posted speed limit of 40 mph. Workers working at the site believe that cars go much faster than the posted speed. A random sample of 36 cars passing through this zone produced a sample mean speed of 48 mph. Perform a hypothesis test to determine if the cars are going faster than the posted speed limit. the population standard deviation is known to be 4 mph. A good answer will include:
1) State the null and alternative hypotheses
2) Draw me a picture
3) Calculate the standard error
4) Calculate the z score for the sample mean
5) Comparison of pvalue and α or comparison of sample z score to α z score
6) State that you accept or reject the null hypothesis