The fetime of a certain brand of electric light bulb is known to have a standard deviation of 54 hours. Suppose that a r
Posted: Sun Oct 03, 2021 12:51 pm
The fetime of a certain brand of electric light bulb is known to have a standard deviation of 54 hours. Suppose that a random sample of 70 bulbs of this brand has a mean lifetime of 484 hour. Find a 99% confidence interval for the true mean lifetime of all light bulbs of this brand. Then give its lower limit and upper imit. Carry your intermediate computations to at least three decimal placet. Hound your answers to one decimal place. (if necessary, consult a list of formulas) Lower limit: 0 Upper limit: