An inventor has developed a new, energy-efficient battery for an iPod speaker. He claims that the battery will run continuously for 5 hours (300 minutes) on a single charge. From his stock of 2000 batteries, the inventor selects a simple random sample of 50 batteries for testing. The batteries run for an average of 295 minutes, with a standard deviation of 20 minutes. Test the null hypothesis that the mean run time is 300 minutes. Use a 0.05 level of significance. (Assume that run times for the population of batteries are normally distributed.)