A manufacturer claims that is lightbulbs will last for an average of 500 hours (or more). A consumer group tested this claim by randomly purchasing and testing 24 of the these light bulbs with the following results; the sample mean was 470 hours, the standard deviation of the sample was 50 hours. assume that the number of hours that the lightbulbs last is normally distributed. what would you conclude about the manufacturer’s claim using .05 significance level? show the test used to draw the conclusion.