A quality-control expert tested a random sample of 29 shoelaces from the Footwear Factory. The breaking strengths of the laces in the sample appeared to be normally distributed with a mean of 480 pounds, and a sample standard deviation of 40 pounds. Find the margin of error for a 99 confidence interval for the mean breaking strength of all Footwear Factory shoelaces. Round your answer to the nearest tenth of a pound. Answer: The margin of error is pounds