各位好:
用lme4包拟合混合线性模型时,对随机效应的定义有些模糊。
包中例子:
> (fm2 <- lmer(Reaction ~ Days + (1|Subject) + (0+Days|Subject), sleepstudy))
Linear mixed-effects model fit by REML
Formula: Reaction ~ Days + (1 | Subject) + (0 + Days | Subject)
Data: sleepstudy
AIC BIC logLik MLdeviance REMLdeviance
1752 1764 -871.8 1752 1744
Random effects:
Groups Name Variance Std.Dev.
Subject (Intercept) 627.508 25.0501
Subject Days 35.858 5.9881
Residual 653.590 25.5654
number of obs: 180, groups: Subject, 18; Subject, 18
Fixed effects:
Estimate Std. Error t value
(Intercept) 251.405 6.885 36.51
Days 10.467 1.560 6.71
Correlation of Fixed Effects:
(Intr)
Days -0.184
从结果看,(1 | Subject)表示Subject水平的random intercept,具体表示什么意思,和random slope model 的区别是什么?如果是(Days | Subject) 是否表示random slope?
麻烦帮我解释一下对模型的设定。
谢谢!


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可否简单解释一下
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