Agriculture Reference
In-Depth Information
Fig. 6.6 Sample selected with a two-stage design
>
set.seed(200694)
>
tst
<
- mstage(framepop,stage
¼
c("cluster",""),
+ varnames
¼
list("strataid2"),size
¼
list(25,rep(4,25)),
+ method
¼
c("srswor"))
>
tstd
<
- getdata(framepop,tst)
>
plot(framepop$xc,framepop$yc, axes
¼
F,cex
¼
0.5,
+ pch
¼
19,xlim
¼
c(0,1),ylim
¼
c(0,1))
>
for (i in seq(0.1,0.9,0.1))
+{
+
abline(h
¼
i,lty
¼
2,lwd
¼
2)
+
abline(v
¼
i,lty
¼
2,lwd
¼
2)
+}
>
box()
>
codpsu
<
- unique(tstd[[2]]$strataid2)
>
for (i in 1:length(codpsu))
+{
+
ybl
<
- (codpsu %% 10)/10
xbl
<
- (codpsu %/% 10)/10
+
+
rect(xbl,ybl,xbl+0.1,ybl+0.1,lwd
¼
1,col
¼
gray(0.9))
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