An experiment was performed in a manufacturing plant by making 5 batches of a chemical using the stan- dard method (A) and 5 batches using a new method (B). The yields, expressed as a percent of a theoretical maximum, were as follows:
Method A: 77.0 69.1 71.5 73.0 73.7
Method B: 78.5 79.6 76.1 76.0 78.5
Find a 99% confidence interval for the difference in the mean yield between the two methods.