一个鸭蛋圆数据的拟合

stats01

x=[ 0, 0.1, 0, 0, 0.01, 0.1, 0.1, 0.1, 0.2, 0.2, 0.2, 0.3, 0.3, 0.3, 0.4, 0.4, 0.4, 0.5, 0.5, 0.5, 0.6, 0.6, 0.6, 0.7, 0.7, 0.7, 0.8, 0.8, 0.8, 0.9, 0.9, 1.0, 1.0, 1.0, 1.1, 1.1, 1.1, 1.1, 1.2, 1.2, 1.2, 1.3, 1.3, 1.4, 1.4, 1.5, 1.5, 1.6, 1.6, 1.7, 1.7, 1.8, 1.8, 1.9, 1.9, 2.0, 2.0, 2.1, 2.1, 2.2, 2.2, 2.3, 2.3, 2.4, 2.4, 2.5, 2.5, 2.6, 2.6, 2.7, 2.7, 2.8, 2.8, 2.9, 2.9, 3.0, 3.0, 3.1, 3.1, 3.2, 3.2, 3.3, 3.3, 3.4, 3.4, 3.5, 3.5, 3.5, 3.5, 3.6, 3.6, 3.6, 3.6, 3.6, 3.7, 3.7, 3.7, 3.7, 3.7, 3.7, 3.7, 3.7, 3.8, 3.8, 3.8, 3.8, 3.8, 3.9, 3.9, 3.9];
y=[ 1.5, 1.9, 1.4, 1.4, 1.6, 1.0, 1.0, 1.0, 2.0, 2.0, 0.81, 2.2, 2.2, 0.69, 2.3, 2.3, 0.59, 0.49, 2.4, 2.4, 0.4, 2.5, 2.5, 2.6, 2.6, 0.31, 2.6, 2.6, 0.23, 2.7, 2.7, 0.18, 2.7, 2.7, 0.11, 2.8, 0.11, 0.11, 2.8, 0.09, 0.09, 2.8, 0.07, 2.8, 0.01, 2.9, 0.01, 2.9, 0, 2.9, 0, 2.9, -0.01, 2.9, 0, 2.9, 0, 2.9, 0.01, 2.8, 0.01, 2.8, 0.07, 2.8, 0.09, 2.8, 0.1, 2.7, 0.12, 2.7, 0.19, 2.7, 0.21, 2.6, 0.28, 2.6, 0.31, 2.5, 0.39, 2.4, 0.42, 2.4, 0.51, 2.3, 0.6, 2.2, 0.69, 2.2, 0.69, 2.1, 0.79, 2.1, 2.1, 2.1, 0.9, 2.0, 2.0, 2.0, 2.0, 2.0, 0.9, 1.9, 1.0, 1.8, 1.8, 1.1, 1.8, 1.5, 1.3, 1.5];
鸭蛋圆数据的拟合，寻找适当的模型并估计参数。有点难，试试本坛拟合爱好者的功力。