c) An inventor has developed a new, energy efficient lawn mower engine. He claims that the engine will run continuously for 5 hours (300 minutes) on a single gallon of regular gasoline. Suppose a simple random sample of 50 engines is tested. The engines run for an average of 295 minutes, with a standard deviation of 20 minutes. Test the hypothesis that the mean run time is 300minutes against the alternative hypothesis that the mean run time is not 300minutes using a 0.05 level of significance. (6 marks)