A milk company took a sample to estimate the amount of milk contained in 1 gallon container. They estimate that 1 gallon milk containers contain...

A milk company took a sample to estimate the amount of milk contained in 1 gallon container. They estimate that 1 gallon milk containers contain between .9877 and 1.0023 gallons of milk at a 99% confidence level. How large was the sample size for them to come to this conclusion? (Please show step by step all the calculations made to solve this problem. Thank you)