RosettaCodeData/Task/Permutation-test/Julia/permutation-test-1.jl

29 lines
760 B
Julia

using Combinatorics
meandiff(a::Vector{T}, b::Vector{T}) where T <: Real = mean(a) - mean(b)
function bifurcate(a::AbstractVector, sel::Vector{T}) where T <: Integer
x = a[sel]
asel = trues(length(a))
asel[sel] = false
y = a[asel]
return x, y
end
function permutation_test(treated::Vector{T}, control::Vector{T}) where T <: Real
effect0 = meandiff(treated, control)
pool = vcat(treated, control)
tlen = length(treated)
plen = length(pool)
better = worse = 0
for subset in combinations(1:plen, tlen)
t, c = bifurcate(pool, subset)
if effect0 < meandiff(t, c)
better += 1
else
worse += 1
end
end
return better, worse
end