You're surprised to learn that instead of -$100, a 0.30 carat costs -$800 carats. Which explanation would make sense? The linear regression is not accurate at predicting the cost of diamonds below 0.40 carats. There is a fixed cost associated with procuring the diamond and offering it for sale, meaning that small diamonds have a relatively high price. The diamond is very high quality as measured by other metrics (e.g., cut, clarity, color) All of the above