Draws, from top to bottom, as
functions of n: E(T) (→ δ),
σ(T), E(T)⁄δ (→ 1).
The parameter δ is given by
δ = −L′ √n
(or = U′ √n),
with L′=(L−μ) ⁄σ
and AQL = Φ(L′).
A useful relation [Weisstein, 2003: eq. 87] to compute the
gamma function for this application is Γ(k+1⁄2) ⁄
Γ(k) ≅ √ k [×1+].
The value Γ(k+1⁄2) is underestimated, but from
k=2.5 the error is less than 5% and decreases rapidly. |
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References:
• Resnikoff & Lieberman, 1957 (see elsewhere)
• Weisstein, E. W., 2003,
"Mathworld" |
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