The military stockpiles different types of drugs for soldiers to use in an emergency. However, replacing these drugs when they reach their expiration date is extremely expensive. The Pentagon wants to test the potency of one stockpiled antibiotic to see if the drug is safe to use. They take a random sample of 81 pills and find a mean potency of 33 micrograms of the active ingredient. If the standard deviation of the sample is 5 micrograms, find the 99% confidence interval for the mean potency of all the pills for this drug. Write an interpretation of this interval in language that a non-statistician would understand.