R語言bootstrap分析(boot)
阿新 • • 發佈:2018-11-11
//## bootstrap分析資料,package = "boot"
> library(boot)
> city
u x
1 138 143
2 93 104
3 61 69
4 179 260
5 48 75
6 37 63
7 29 50
8 23 48
9 30 111
10 2 50
> library(boot)
> beta < -function(formula,data,indices){
+ d < -data[indices,]
+ fit < -lm(formula, data=d)
+ return(fit$coef) ## 將coef[2]改為coef,會出現stu
+ }
> result <- boot(data=women,statistic=beta,R=500,formula=weight~height)
> boot.ci(result)
BOOTSTRAP CONFIDENCE INTERVAL CALCULATIONS
Based on 500 bootstrap replicates
CALL :
boot.ci(boot.out = result)
Intervals :
Level Normal Basic Studentized
95 % (-102.22, -71.83 ) (-102.38, -72.16 ) (-102.92, -72.65 )
Level Percentile BCa
95% (-102.88, -72.65 ) (-102.28, -72.29 )
Calculations and Intervals on Original Scale
//## function :The second will be a vector of indices, frequencies or weights which define the bootstrap sample.