Department store accepts three types of credit cards, MasterCard, Visa, and their own store card. Charges are normally distributed. A random sample of 18 credit card purchases included 6 MasterCard, 7 Visa, and 5 store charges. The total sum of squares calculated was 7,114, and the sum of squares within groups (SSE) was 3776.0333. At the .05 significance level, can we conclude there is a difference in the mean amounts charged per purchase on the three cards?