Problem 3. The yield stress of many metals, o,, varies with the size of the grains as given in the table below. mm 0.0018 00025 0.004 0,007 o,( MPa) | 530 0.016 155 115 Find the quadratic function that best fits the data. Plot the data points (circle markers) and the quadratic equation as a solid line. Use the quadratic equation to estimate the yield stress of a specimen with a grain size of 0.003 mm. You can use the polynomial regression code written in class. Answer: 404.934