studynum <-c(1, 2, 3, 4, 5)
y <-c(0.284, 0.224, 0.360, 0.785, 0.492)
w <-c(14.63, 17.02, 9.08, 33.03, 5.63)
genData2 <-data.frame(cbind(studynum, y, w))
library(nlme)
re.teo<-lme(y~1,data=genData2,random=~1|studynum, method="REML", weights=varFixed(~w))
summary(re.teo)

运行结果如下：
Linear mixed-effects model fit by REML

Data: genData2

AIC
BIC


logLik


5.033622
3.192505
0.483189

Random effects:

Formula: ~1 | studynum

(Intercept)

Residual
StdDev: 4.205259e-06
0.04701933

Variance function:

Structure: fixed weights

Formula: ~w
Fixed effects: y ~ 1

Value
Std.Error

DF

t-value
p-value
(Intercept)

0.4119562

0.0704743
5
5.845481

0.0021
此处的自由度为什么是5？

Standardized Within-Group Residuals:

1

2
3
4
5
-0.7114801 -0.9689479 -0.3667061
1.3804766
0.7174588
attr(,"label")
[1] "Standardized residuals"

Number of Observations: 5
Number of Groups: 5