Statistics/Chi-squared distribution: Difference between revisions
m
gamma
m (correct formula) |
m (gamma) |
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Line 82:
""" gamma function
function gamma(
p = [ 0.99999999999980993, 676.5203681218851, -1259.1392167224028,
771.32342877765313, -176.61502916214059, 12.507343278686905,
-0.13857109526572012, 9.9843695780195716e-6, 1.5056327351493116e-7 ]
x = a
return π / (sinpi(x) * gamma(1.0 - x))
else
x -= 1.0
t = p[1]
for i in 1:8
t += p[i+1] / (x + i)
end
end
w = x + 7.5
return sqrt(2.0 * π) * w^(x+0.5) * exp(-w) * t
end
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