A drug manufacturer produces and antibiotic and a large fermentation vats (containers) to determine the average potency for the batch of antibiotics

 A drug manufacturer produces and antibiotic and a large fermentation vats (containers)  to determine the average potency for the batch of antibiotics being prepared, the VAT is sampled at 9 randomly selected locations. The nine potency readings have the mean of 8.9 and the standard deviation of 0.33. We assume the data are a random sample and that potency reading follow a normal distribution.