Analysis of Variance and Effect Sizes for Univariate Statistics

Computes a Wald test which tests equality of means (univariate analysis of variance). In addition, the \(d\) and \(\eta\) effect sizes are computed.

BIFIE.univar.test(BIFIE.method, wald_test=TRUE)

# S3 method for BIFIE.univar.test
summary(object,digits=4,...)

Arguments

BIFIE.method

Object of class BIFIE.univar

wald_test

Optional logical indicating whether a Wald test should be performed.

object

Object of class BIFIE.univar.test

digits

Number of digits for rounding output

...

Further arguments to be passed

Value

A list with following entries

stat.F

Data frame with \(F\) statistic for Wald test

stat.eta

Data frame with \(\eta\) effect size and its inference

stat.dstat

Data frame with Cohen's \(d\) effect size and its inference

...

More values

See also

BIFIE.univar

Examples

#############################################################################
# EXAMPLE 1: Imputed TIMSS dataset - One grouping variable
#############################################################################

data(data.timss1)
data(data.timssrep)

# create BIFIE.dat object
bdat <- BIFIEsurvey::BIFIE.data( data.list=data.timss1, wgt=data.timss1[[1]]$TOTWGT,
           wgtrep=data.timssrep[, -1 ] )

#**** Model 1: 3 variables splitted by book
res1 <- BIFIEsurvey::BIFIE.univar( bdat, vars=c("ASMMAT", "ASSSCI","scsci"),
                    group="books")
summary(res1)
# analysis of variance
tres1 <- BIFIEsurvey::BIFIE.univar.test(res1)
summary(tres1)

#**** Model 2: One variable splitted by gender
res2 <- BIFIEsurvey::BIFIE.univar( bdat, vars=c("ASMMAT"), group="female" )
summary(res2)
# analysis of variance
tres2 <- BIFIEsurvey::BIFIE.univar.test(res2)
summary(tres2)

if (FALSE) {
#**** Model 3: Univariate statistic: math
res3 <- BIFIEsurvey::BIFIE.univar( bdat, vars=c("ASMMAT") )
summary(res3)
tres3 <- BIFIEsurvey::BIFIE.univar.test(res3)

#############################################################################
# EXAMPLE 2: Imputed TIMSS dataset - Two grouping variables
#############################################################################

data(data.timss1)
data(data.timssrep)

# create BIFIE.dat object
bdat <- BIFIEsurvey::BIFIE.data( data.list=data.timss1, wgt=data.timss1[[1]]$TOTWGT,
                  wgtrep=data.timssrep[, -1 ] )

#**** Model 1: 3 variables splitted by book and female
res1 <- BIFIEsurvey::BIFIE.univar(bdat, vars=c("ASMMAT", "ASSSCI","scsci"),
                  group=c("books","female"))
summary(res1)

# analysis of variance
tres1 <- BIFIEsurvey::BIFIE.univar.test(res1)
summary(tres1)

# extract data frame with Cohens d statistic
dstat <- tres1$stat.dstat

# extract d values for gender comparisons with same value of books
# -> 'books' refers to the first variable
ind <- which(
  unlist( lapply( strsplit( dstat$groupval1, "#"), FUN=function(vv){vv[1]}) )==
  unlist( lapply( strsplit( dstat$groupval2, "#"), FUN=function(vv){vv[1]}) )
        )
dstat[ ind, ]
}