3. A business researcher wants to determine whether the type of gas preferred is independent of a person's income. She takes a random sample of gas purchasers and asks them about their income and the gas they purchase. The following are the data. Type of gas Regular Premium Extra premium Income Less than $30,000 85 16 6 $30,000 to $49,999 102 27 13 $50,000 to $100,000 36 22 15 More than $100,000 15 23 25 At a = 0.01, test if the type of gas purchased and income are independent