A real estate company is trying to determine if they can predict the price of a house given the number of bedrooms, number of bathrooms, and color of the exterior of the home. The data for ten houses is below. House ID Price Bedrooms Bathrooms Color of Exterior 1 250,000 4 3 Green 2 190,000 3 2 White 3 150,000 2 Blue 4 170,000 2 Green 5 175,000 3 2 Green 6 225,000 4 3 Blue 7 200,000 3 2 Blue 8 210,000 4 2 White 9 185,000 2 2 Green 10 165,000 2 1 White How many dummy variables are needed to represent the color of the exterior of the home