The lifetime of a certain brand of electric light bulb is

Last updated: 4/25/2023

The lifetime of a certain brand of electric light bulb is known to have a standard deviation of 47 hours Suppose that a random sample of 80 bulbs of this brand has a mean lifetime of 479 hours Find a 90 confidence Interval for the true mean lifetime of all light bulbs of this brand Then give its lower limit and upper limit Carry your Intermediate computations to at least three decimal places Round your answers to one decimal place If necessary consult a list of formulas Lower limit Upper limit