Ruth was attempting to estimate a model for her small business's overhead costs. She is 99.9% sure that overhead costs are driven primarily by production, but she also knows that this cost isn't entirely variable. So the grabbed the last 8 months of production and overhead cost data, listed it out, and plotted it as follows. # of Units Produced Month 1 2 3 7 250 210 280 340 360 320 270 290 Overhead Cost $2.730 1.990 2440 3.070 2,740 2,980 2440 3,240