Manuals/calci/EXPONDIST

EXPONDIST(x,lambda,cumulative)


  • is the value of the function
  • is the value of the rate parameter
  • is the logical value like TRUE or FALSE

Description

  • This function gives the Exponential Distribution. This distribution is used to model the time until something happens in the process.
  • This describes the time between events in a Poisson process i.e, a process in which events occur continuously and independently at a constant average rate.
  • For e.g Time between successive vehicles arrivals at a workshop.
  • Exponential distribution is the only continuous memoryless random distribution. It is a continuous analog of the Geometric distribution.
  • In  ,   is the value of the function,   is called rate parameter and   is either TRUE or FALSE.
  • This function will give the Cumulative Distribution Function when   is TRUE, otherwise it will give the Probability Density Function , when   is FALSE.
  • Suppose we are not giving the   value, by default it will consider the   value is FALSE.
  • This function will give the error result when
1.   or   is non-numeric.
2.   or  

The Probability Density Function of an Exponential Distribution is:   or

 
  • where   is the rate parameter and   is the Heaviside step function
  • This function is valid only on the interval [0,infinity].

The Cumulative Distribution Function is :   or

 

ZOS Section

  • The syntax is to calculate EXPONDIST in ZOS is  .
    • where   is the value of the function
    •   is the value of the rate parameter
    •   is the logical value like TRUE or FALSE.
  • For e.g.,EXPONDIST(11..12,2.3..3.3..0.4,FALSE)
Exponential Distribution

Examples

Question : If jobs arrive at an average of 15 seconds,   per minute, what is the probability of waiting 30 seconds, i.e 0.5 min? Here   and  

  • =EXPONDIST(0.5,5,TRUE) = 0.917915001
  • =EXPONDIST(5,3,TRUE) = 0.999999694
  • =EXPONDIST(0.4,2,FALSE) = 0.898657928"

See Also

References