R Manual

:::

Loading Packages

Haven

if (!require(haven)){
  install.packages("haven", dependencies = TRUE)
  require(haven)
}

Psych

if (!require(psych)){
  install.packages("psych", dependencies = TRUE)
  require(psych)
}

Summarytools

if (!require(summarytools)){
  install.packages("summarytools", dependencies = TRUE)
  require(summarytools)
}

:::

Import Data

SPSS

dataset <- read_sav("Harry Potter Data.sav")

Scoring Variable

Create dataframe with only relevant variables to work with.

Extraversion <- data.frame (dataset$FFM_1, dataset$FFM_6, dataset$FFM_11, dataset$FFM_16, dataset$FFM_21, dataset$FFM_26, dataset$FFM_31, dataset$FFM_36)

Create list of ‘keys’. The numbers just refer to the order of the question in the data.frame() you just made. The most important thing is to mark the questions that should be reversed scored with a ‘-’.

Extraversion.keys <- make.keys(Extraversion, list(Extraversion=c(1,-2,3,4,-5,6,-7,8)))

Score the scale.

Extraversion.scales <- scoreItems (Extraversion.keys, Extraversion)

Save the scores.

Extraversion.scores <- Extraversion.scales$scores

Save the scores back in ‘dataset’.

dataset$Extraversion <- Extraversion.scores[,]

Print the cronbach alpha.

Extraversion.scales$alpha

      Extraversion
alpha    0.8141661