View source for Engineering Tables/Normal Distribution/Tail Function Graph

The tail function is the area under the normal distribution N(0,1) between ''x'' and +∞:
::<math>\mbox{T}(x) = \int\limits_x^\infty  {{1 \over {\sqrt {2\pi } }}\exp \left( { - {{y^2 } \over 2}} \right)dy} </math>

[[image:Tail Function Graph.svg|center]]

For ''x'' > 6.5, the tail function can be approximated as:
::<math>\mbox{T}(x) = {1 \over {x\sqrt { 2\pi } }}\exp \left( { - {{x^2 } \over 2}} \right) </math>

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