The operation manager at the light bulb factory wants to determine whether there is any difference in the average life expectancy of bulbs manufactured on two different types of machines. The process standard deviation of Machine 1 is 110 hours and of Machine II is 125 hours. A random sample of 25 light bulbs obtained from Machine 1 indicates a sample mean of 375 hours, and a similar sample of 25 from Machine II indicates a sample mean of 362 hours.
(a) Using the 0.05 level of significance, is there any evidence of a difference in the average life of bulbs produced by the two types of machines?