7. 20 Whole Foods is an all- natural grocery chain that has 50,000 square foot stores , up from the industry. average of 34, 000 square feet . Sales per square foot of supermarkets average just under $400 per square foot , as reported by USA Today in an article on " A whole new ballgame in grocery shopping . " Suppose that sales per square foot in the most recent fiscal year are recorded for a random sample of 10 Whole Foods supermarkets . The data ( sales dollars per square foot ) are as follows : 854 , 858, 801 , 892, 849, 807, 894, 863, 829, 815. Using the fact that * = 846. 2 and 5 = 32. 866 , find a 95 percent confidence interval for the true mean sales dollars per square foot for all Whole Foods supermarkets during the most recent fiscal year . Are we 95 percent confident that* this mean is greater than $800 , the historical average for Whole Foods ? @ Whole Foods