已知一组实验数据如下 x2 4 6 8 y2 11 28 40 试用最小二乘法求一次和二次拟合多项式 并分别算出均方误差与最大偏差

1.y=-12.5+6.55x, \sqrt { \sum \delta _{i}^{2}}=3.27,max \mid \delta _{i} \mid =2.7 y=-8.75+4.675x+0.1875x^{2}, \sqrt { \sum \delta _{i}^{2}}=2.91,max \mid \delta _{i} \mid =2.95