lib/distribution/f/statistics2.rb
module Distribution
module F
module Statistics2_
class << self
# F cumulative distribution function (cdf).
#
# Returns the integral of F-distribution
# with k1 and k2 degrees of freedom
# over [0, x].
# Distribution::F.cdf(20,3,2)
#
def cdf(x, k1, k2)
Statistics2.fdist(k1, k2, x)
end
# Return the P-value of the corresponding integral with
# k degrees of freedom
#
# Distribution::F.p_value(0.95,1,2)
# Statistics2 have some problem with extreme values
def quantile(pr, k1, k2)
Statistics2.pfdist(k1, k2, pr)
end
alias_method :p_value, :quantile
end
end
end
end