Manuals/calci/GAMMADIST

GAMMADIST(x,alpha,beta,cumulative,accuracy)


  • is the value of the distribution.
  • and are the value of the parameters.
  • is the logical value like true or false.
  • gives accurate value of the solution.

Description

  • This function gives the value of the Gamma Distribution.
  • The Gamma Distribution can be used in a queuing models like, the amount of rainfall accumulated in a reservoir.
  • This distribution is the Continuous Probability Distribution with two parameters   and  .
  • In  ,   is the value of the distribution,   is called shape parameter and   is the rate parameter of the distribution and   is the logical value like TRUE or FALSE.
  • If   is TRUE, then this function gives the Cumulative Distribution value and if is FALSE then it gives the Probability Density Function.
  •   gives accurate value of the solution.
  • The gamma function is defined by :

 .

  • It is for all complex numbers except the negative integers and zero.
  • The Probability Density Function of Gamma function using Shape, rate parameters is:

 , for

 , where   is the natural number(e = 2.71828...),   is the number of occurrences of an event, and   is the Gamma function.
  • The Standard Gamma Probability Density function is:

 .

  • The Cumulative Distribution Function of Gamma is :

 , or

  for any positive integer  .
  • When alpha is a positive integer, then the distribution is called Erlang distribution.
  • If the shape parameter   is held fixed, the resulting one-parameter family of distributions is a natural exponential family.
  • For a positive integer  , when  ,  , and  , GAMMADIST returns (1 - CHIDIST(x)) with   degrees of freedom.
  • This function shows the result as error when
1.Any one of the argument is non numeric
2. ,   or  .

ZOS

  • The syntax is to calculate GAMMADIST in ZOS is  .
    •   is the value of the distribution,
    •   and   are the value of the parameters
    •   is the logical value like true or false.
    •   gives accurate value of the solution.
  • For e.g.,GAMMADIST(10.45,2.8,6.4,TRUE,0.9)

GAMMADIST(10.45,2.8,6.4,FALSE,0.9)

Gamma Distribution

Examples

  1. GAMMADIST(8.15372,5,7,TRUE)=0.006867292
  2. GAMMADIST(20.78542,2,6,TRUE)=0.860283293
  3. GAMMADIST(20.78542,2,6,FALSE)=0.01806997
  4. GAMMADIST(45.6523,9,4,FALSE)=0.019724471
  5. GAMMADIST(8.15372,5,7,TRUE,0.5)= 0.00693316259
  6. GAMMADIST(8.15372,5,7,TRUE,0.9)=0.0067648564

See Also

References

Gamma Distribution