WeibullDataSet.CalculateBestFit

Member of: SynthesisAPI.WeibullDataSet

Performs goodness of fit tests to find the distribution that best fits the data set. Returns a message box that shows the estimated parameters of the distribution that best fits the data. (Similar to the Distribution Wizard feature in Weibull++). Use the BestFitSettings property of the class to specify the criteria for evaluating the fit.

In addition, the method automatically creates a retrievable cModel object that represents the fitted model from the life data analysis.

Syntax

.CalculateBestFit

Example

VBA

 'Declare a new WeibullDataSet object.  
  Dim WDS As New WeibullDataSet

 'Add failure times to the data set. 
  Call WDS.AddFailure(100, 1)
  Call WDS.AddFailure(120, 1)
  Call WDS.AddFailure(130, 1)  
 
 'Consider the normal, lognormal and 2-parameter Weibull distributions in the evaluation. 
  WDS.BestFitSettings.AllowExponential1 = False
  WDS.BestFitSettings.AllowExponential2 = False
  WDS.BestFitSettings.AllowNormal = True
  WDS.BestFitSettings.AllowLognormal = True
  WDS.BestFitSettings.AllowWeibull2 = True
  WDS.BestFitSettings.AllowWeibull3 = False
  WDS.BestFitSettings.AllowGamma = False
  WDS.BestFitSettings.AllowGenGamma = False
  WDS.BestFitSettings.AllowLogistic = False
  WDS.BestFitSettings.AllowLoglogistic = False
  WDS.BestFitSettings.AllowGumbel = False
 
 'Perform the goodness of fit tests. 
  Call WDS.CalculateBestFit()
 
 'Retrieve the fitted life distribution model. 
  Dim model As cModel
  Set model = WDS.FittedModel

 'Using the model, calculate the reliability at 100 hrs and display the result. 
  Dim r As Double
  r = model.reliability(100)
  MsgBox("Reliability at 100 hrs: " & r)

VB.NET

 'Declare a new WeibullDataSet object.  
  Dim WDS As New WeibullDataSet

 'Add failure times to the data set. 
  WDS.AddFailure(100, 1)
  WDS.AddFailure(120, 1)
  WDS.AddFailure(130, 1)  
 
 'Consider the normal, lognormal and 2-parameter Weibull distributions in the evaluation. 
  WDS.BestFitSettings.AllowExponential1 = False
  WDS.BestFitSettings.AllowExponential2 = False
  WDS.BestFitSettings.AllowNormal = True
  WDS.BestFitSettings.AllowLognormal = True
  WDS.BestFitSettings.AllowWeibull2 = True
  WDS.BestFitSettings.AllowWeibull3 = False
  WDS.BestFitSettings.AllowGamma = False
  WDS.BestFitSettings.AllowGenGamma = False
  WDS.BestFitSettings.AllowLogistic = False
  WDS.BestFitSettings.AllowLoglogistic = False
  WDS.BestFitSettings.AllowGumbel = False
 
 'Perform the goodness of fit tests. 
  WDS.CalculateBestFit()
 
 'Retrieve the fitted life distribution model. 
  Dim model As cModel
  model = WDS.FittedModel

 'Using the model, calculate the reliability at 100 hrs and display the result. 
  Dim r As Double
  r = model.reliability(100)
  MsgBox("Reliability at 100 hrs: " & r)