Problem
About 5% of cars built after 2007 fail their smog test with a standard deviation of 1.7. A car company is being reviewed by the EPA for failing to design their cars according to the latest emission standards. A random sample from California drivers (who own the make and model under review) found that on average the cars failed at a rate of 20% with a standard deviation of 4.5. Which hypothesis test should be used to determine whether the sample contains more than the average car built after 2007?