R语言中 fitted()和predict()的区别

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R对数据做线性拟合后，命令fitted(lm.sol)和predict(lm.sol)有什么区别？分别是怎么计算的

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关键词：predict fitted Pred edi fit

假设你是做的模型是y~x,给的值是(x1,x2,...,xn),(y1,y2,...,yn)
fitted()的结果是你得到相应的模型后，(x1,x2,...,xn)相应的值，也就是(y1,y2,...,yn)的估计值
predict()中你可以用(x1,x2,...,xn)的值，也可以用新的值,看下你的预测值为多少。

你可以找一组数据试试，结果如何。
fit<-lm(weight~height,data=women)
fitted(fit)
predict(fit,newdata=data.frame(height=90))##将90代入看结果如何
这是R in action中的例子

fitted是拟合值，predict是预测值。你的模型是基于给定样本的值建立的，在这些给定样本上做预测就是拟合。在新样本上做预测就是预测。lz可以仔细查一下相关概念。

原来如此

请问predict（type=‘prob’和type=‘response’）输出的结果是什么呢？我怎么跑出来结果都是一样的
求指导

你们好啊 发表于 2015-8-6 17:49
请问predict（type=‘prob’和type=‘response’）输出的结果是什么呢？我怎么跑出来结果都是一样的
求指导 ...

predict()中未见有type参数。

---------------------------------------------------------------------------------------------------
predict {stats}        R Documentation
Model Predictions
Description

predict is a generic function for predictions from the results of various model fitting functions. The function invokes particular methods which depend on the class of the first argument.
Usage

predict (object, ...)

Arguments
object        

a model object for which prediction is desired.
...        

additional arguments affecting the predictions produced.
Details

Most prediction methods which are similar to those for linear models have an argument newdata specifying the first place to look for explanatory variables to be used for prediction. Some considerable attempts are made to match up the columns in newdata to those used for fitting, for example that they are of comparable types and that any factors have the same level set in the same order (or can be transformed to be so).

Time series prediction methods in package stats have an argument n.ahead specifying how many time steps ahead to predict.

Many methods have a logical argument se.fit saying if standard errors are to returned.
Value

The form of the value returned by predict depends on the class of its argument. See the documentation of the particular methods for details of what is produced by that method.
References

Chambers, J. M. and Hastie, T. J. (1992) Statistical Models in S. Wadsworth & Brooks/Cole.

参考?predict.lm中对type的说明

了解了

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