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Contents
module Statsample
module Anova
# One Way Anova
# Example:
# v1=[2,3,4,5,6].to_vector(:scale)
# v2=[3,3,4,5,6].to_vector(:scale)
# v3=[5,3,1,5,6].to_vector(:scale)
# anova=Statsample::Anova::OneWay.new([v1,v2,v3])
# puts anova.f
# puts anova.significance
class OneWay
def initialize(vectors)
@vectors=vectors
end
# Total sum
def sum
@vectors.inject(0){|a,v| a+v.sum}
end
# Total mean
def mean
sum.quo(n)
end
# Total sum of squares
def sst
m=mean.to_f
@vectors.inject(0) {|total,vector|
total+vector.sum_of_squares(m)
}
end
# Sum of squares within groups
def sswg
@vectors.inject(0) {|total,vector|
total+vector.sum_of_squares
}
end
# Sum of squares between groups
def ssbg
m=mean
@vectors.inject(0) {|total,vector|
total+(vector.mean-m).square*vector.size
}
end
# Degrees of freedom within groups
def df_wg
@vectors.inject(0) {|a,v| a+(v.size-1)}
end
# Degrees of freedom between groups
def df_bg
@vectors.size-1
end
# Total Degrees of freedom
def df_total
n-1
end
# Total number of cases
def n
@vectors.inject(0){|a,v| a+v.size}
end
# Fisher
def f
k=@vectors.size
(ssbg*(n-k)) / (sswg*(k-1))
end
# Significance of Fisher
def significance
if HAS_GSL
GSL::Cdf.fdist_Q(f,df_bg,df_wg)
else
raise "Need Ruby/GSL"
end
end
end
end
end
Version data entries
5 entries across 5 versions & 1 rubygems