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查看完整版本 : [求助]最小二乘法的应用


一剑飘红
2009-03-24, 20:44
已知y=[3750.96,3792.23,3826.58,3871.51,3924.32,3963.1,3993.09,4029.56,4070.07,4121.19,4169.85,4208.88,4234.91,4261.37,4285.91,4313.3,4341.2,4369.63,4400.09,4422.28,4446.86,4467.46,4501.22,4519.84,4535.98,4551.58,4577.22,4602.11,4629.43];
b=[1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006];
x=b-1978;
要用y=m/(1+(m/3750.96-1)*exp(-r*x))拟合,求m和r,应该如何编程?

slgu
2009-03-25, 00:02
[m,r]=[5026.8471, 0.048181846]
R^2 = 0.9989
若用模型:
y=A./(1+B*exp(-C*x));
[A B C]=[4989.763, 0.33361634, 0.050650549]
R^2=0.99905
也许效果会更好一些。