b. According to a national study the average consumer unit spent $1736 on apparel and services in 2012. That same year, 25 consumer units in the Northeast were surveyed about their annual expenditures, in dollars, on apparel and services. At the 5% significance level, the data provide sufficient evidence to conclude that the 2012 mean annual expenditure on apparel and services for consumer units in the Northeast differed from the national mean of $1736. (Note: x = $1921.38 and s = $350.39.) The confidence interval is (Round to two decimal places as needed.)