Average Cost Calculation

1).  Which is cheaper:  eating in or dining out?  The mean cost of a flank steak, broccoli, and rice bought at the grocery store is $13.04.  A sample of 100 neighborhood restaurants showed an average price of $12.75 with a standard deviation of $2 for a comparable restaurant meal.  At 95% confidence, is there evidence to show that the average cost of a restaurant meal is less than fixing a comparable meal at home?  What is your conclusion?   Explain your conclusions.