3. lighthouses are constructed to guide ships travelling in rocky waters and to allow sailing at night. there are many ways to report the size of a lighthouse. however, the height is usually measured from the base of the tower to the top of the ventilator ball. to predict the mean height of all lighthouses in france, we look to randomly select a sample of lighthouses in france. assume the standard deviation of the size of lighthouses is 8 meters. how large a sample is necessary to ensure that the confidence level is 95% and that the estimated mean height of lighthouses does not differ from the true mean height by more than 1 meter?