A liquor wholesaler is interested in assessing the effect of the price of a premium scotch whiskey on the quantity sold. The results in the accompanying table on price, in dollars. and sales, in cases, were obtained from a sample of 8 weeks of sales records. PRICE SALES 19.2 20.5 19.7 21.3 20.8 19.9 17.8 17.2 25.4 14.7 18.6 124 15.7 29.2 35.2 Find a 95% confidence interval for the expected change in sales resulting from a 51 in- crease in price.