Each of three supermarket chains in the Denver area claims to have the lowest overall prices. As part of an investigative study on supermarket advertising, a local television station conducted a study by randomly selecting nine grocery items. Then, on the same day. an intern was sent to each of the three stores to purchase the nine items. From the receipts, the following data were recorded. Item 1 Super $1.02 Ralph's $1.32 Lowblaws $1.32 1.07 2.46 2.46 3 1.14 1.23 1.37 4 1.10 1.29 1.29 1.21 1.37 1.37 $3.54 3.54 2.40 7 5.17 5.17 5.05 4.36 4.36. 4.15 3.75 3.75 4.21