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(Created page with '====Reliability Function==== For the lognormal distribution, the reliability for a mission of time <math>T</math> , starting at age 0, is given by: <br> ::<math>R(T)=\mathop{}_{…')
 
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For the lognormal distribution, the reliability for a mission of time  <math>T</math> , starting at age 0, is given by:
For the lognormal distribution, the reliability for a mission of time  <math>T</math> , starting at age 0, is given by:
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<br>
::<math>R(T)=\mathop{}_{T}^{\infty }f(t)dt</math>
::<math>R(T)=\int_{T}^{\infty }f(t)dt</math>
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<br>
:or:
:or:
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<br>
::<math>R(T)=\mathop{}_{{{T}^{^{\prime }}}}^{\infty }\frac{1}{{{\sigma }_{{{T}'}}}\sqrt{2\pi }}{{e}^{-\tfrac{1}{2}{{\left( \tfrac{t-\overline{{{T}'}}}{{{\sigma }_{{{T}'}}}} \right)}^{2}}}}dt</math>
::<math>R(T)=\int_{{{T}^{^{\prime }}}}^{\infty }\frac{1}{{{\sigma }_{{{T}'}}}\sqrt{2\pi }}{{e}^{-\tfrac{1}{2}{{\left( \tfrac{t-\overline{{{T}'}}}{{{\sigma }_{{{T}'}}}} \right)}^{2}}}}dt</math>
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<br>
There is no closed form solution for the lognormal reliability function. Solutions can be obtained via the use of standard normal tables.
There is no closed form solution for the lognormal reliability function. Solutions can be obtained via the use of standard normal tables.
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<br>
<br>
<br>

Revision as of 00:50, 7 February 2012

Reliability Function

For the lognormal distribution, the reliability for a mission of time [math]\displaystyle{ T }[/math] , starting at age 0, is given by:

[math]\displaystyle{ R(T)=\int_{T}^{\infty }f(t)dt }[/math]


or:


[math]\displaystyle{ R(T)=\int_{{{T}^{^{\prime }}}}^{\infty }\frac{1}{{{\sigma }_{{{T}'}}}\sqrt{2\pi }}{{e}^{-\tfrac{1}{2}{{\left( \tfrac{t-\overline{{{T}'}}}{{{\sigma }_{{{T}'}}}} \right)}^{2}}}}dt }[/math]


There is no closed form solution for the lognormal reliability function. Solutions can be obtained via the use of standard normal tables.