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Contents
module Statsample
module SPSS
class << self
# Export a SPSS Matrix with tetrachoric correlations .
#
# Use:
# ds=Statsample::Excel.read("my_data.xls")
# puts Statsample::SPSS.tetrachoric_correlation_matrix(ds)
def tetrachoric_correlation_matrix(ds)
dsv=ds.dup_only_valid
# Delete all vectors doesn't have variation
dsv.fields.each{|f|
if dsv[f].factors.size==1
dsv.delete_vector(f)
else
dsv[f]=dsv[f].dichotomize
end
}
tcm=Statsample::Bivariate.tetrachoric_correlation_matrix(dsv)
n=dsv.fields.collect {|f|
sprintf("%d",dsv[f].size)
}
meanlist=dsv.fields.collect{|f|
sprintf("%0.3f", dsv[f].mean)
}
stddevlist=dsv.fields.collect{|f|
sprintf("%0.3f", dsv[f].sd)
}
out=<<-HEREDOC
MATRIX DATA VARIABLES=ROWTYPE_ #{dsv.fields.join(",")}.
BEGIN DATA
N #{n.join(" ")}
MEAN #{meanlist.join(" ")}
STDDEV #{stddevlist.join(" ")}
HEREDOC
tcm.row_size.times {|i|
out +="CORR "
(i+1).times {|j|
out+=sprintf("%0.3f",tcm[i,j])+" "
}
out +="\n"
}
out+="END DATA.\nEXECUTE.\n"
end
end
end
end
Version data entries
38 entries across 38 versions & 1 rubygems