R: Examples for 'survey::svyttest'

### ** Examples

data(api)
dclus2<-svydesign(id=~dnum+snum, fpc=~fpc1+fpc2, data=apiclus2)
tt<-svyttest(enroll~comp.imp, dclus2)
tt

	Design-based t-test

data:  enroll ~ comp.imp
t = -2.8882, df = 36, p-value = 0.006518
alternative hypothesis: true difference in mean is not equal to 0
95 percent confidence interval:
 -384.24757  -67.22654
sample estimates:
difference in mean 
         -225.7371

confint(tt, level=0.9)

[1] -357.68999  -93.78413
attr(,"conf.level")
[1] 0.9

svyttest(enroll~I(stype=="E"),dclus2)

	Design-based t-test

data:  enroll ~ I(stype == "E")
t = -9.8291, df = 36, p-value = 9.826e-12
alternative hypothesis: true difference in mean is not equal to 0
95 percent confidence interval:
 -706.306 -464.688
sample estimates:
difference in mean 
          -585.497

svyttest(I(api00-api99)~0, dclus2)

	Design-based one-sample t-test

data:  I(api00 - api99) ~ 0
t = 9.0704, df = 38, p-value = 4.782e-11
alternative hypothesis: true mean is not equal to 0
95 percent confidence interval:
 20.02455 31.53117
sample estimates:
    mean 
25.77786