\fA restaurant wants to test a new in-store marketing scheme in a small number of stores before rolling it out nationwide. The new ad promotes a premium drink that they want to increase the sales of. 8 locations are chosen at random and the number of drinks sold are recorded for 2 months before the new ad campaign and 2 months after. The average difference in the sales quantity (after - before) is -112.292 with a standard deviation of 33.0108. Calculate a 99% confidence interval to estimate the true average difference in nationwide sales quantity before the ad campaign and after