PsiMetalog2(coefficients)

Returns a variate from a meta-logistic distribution approximated by a table of historical data. 

The coefficients argument is either a range or an array of two to sixteen (2 to 16) numerical elements.  

PsiMetalog2 differs from PsiMetalog in the following ways.

  1. Fitting a distribution using PsiMetalog2Fit guarantees a feasible or valid distribution. 
  2. Fitting is improved when using the PsiMetalog2 distribution, even though PsiMetalog2 lacks bound arguments. 
  3. PsiMetalog2 behaves the same as PsiMetalog when there are six or fewer coefficients (n ≤ 6). All statistics and curves will be identical for n ≤ 6.
  4. PsiMetalog2 has three additional statistics:  modes, anti-modes and feasible. 

Parameters

coefficients

Range of Function Values

7-Term Quantile Function

See the website, http://metalogdistributions.com/, for more information.

Feasibility

Indicates whether the distribution, as defined by its coefficients, is feasible or infeasible.

Feasibility = True:  Indicates the fitting succeeded with a feasible distribution, making it suitable for use in a simulation model.

Feasibility = False:  Indicates that the fitting succeeded with an infeasible distribution, making it not suitable for use in a simulation model.

Feasibility = N/A:  Indicates that fitting failed. The reason is unknown.  The distribution with returned coefficients should not be used in a simulation model.    

Modes

Returns all local maximums (for the x-axis) on the PDF function. Only Metalog distributions may have more than one mode. This is one major reason why Metalog distributions are superior in fitting complicated data.

Anti-modes

Returns all local minimums on the PDF function. Only Metalog distributions may have anti-modes; other distributions do not exhibit anti-modes. Note:  There must be 2 modes and more than 5 coefficients in order for an anti-mode to exist. 

See the website, http://metalogdistributions.com/, for more information.