A manufacturer of electric lamps is testing a new production method that will be considered acceptable if the lamps produced by this method result in a population with an average life of 240 hours. A sample of 21 lamps produced by this method has an average life of 232 hours and a standard deviation equal to 30. They are going to do the hypothesis of validity for this new manufacturing process if it is accepted with a risk equal to or less than 5%.
What should be Null and Alternative Hyp.