Change the Fit Method of a Reliability Distribution Analysis

The Kolmogorov-Smirnov test is a Goodness of Fit (GOF) test applied to Reliability Distribution Analyses to determine how well the data fits the analytical curve. When you create an analysis, by default, the fit method is set to Least Squares.

After the analysis is created, you can modify the fit method to one of the following:

Least Squares: A curve-fitting estimation method that relies on linear regression techniques to estimate the parameters for the distribution.
Maximum Likelihood Estimators: A curve-fitting estimation method that maximizes the likelihood function for a given population. This method includes a survivor function that estimates changes in reliability as the piece of equipment or location survives beyond a certain age.

You can change the fit method in the Analysis Summary workspace or after selecting any of the plot tabs in the left pane.

Steps

Access a Reliability Distribution Analysis for which you want to modify the fit method.
If you want to change the fit method from the Analysis Summary workspace:
1. In the bottom section, select Distribution Options, and then select .
  
  The Fit Method list is enabled.
2. From the Fit Method list, select the desired fit method, and then select .
  
  The analysis is recalculated based on the selected fit method.
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If you want to change the fit method after selecting one of the plot tabs (e.g., Probability Plot tab):
1. In the left pane, select the Probability Plot tab.
  
  The Probability Plot appears in the workspace.
2. In the upper-right corner of the workspace, select Distribution Options, and then select Fit Method.
  
  The Select Fit Method window appears.
3. Select the desired fit method, and then select OK.
  
  The analysis is recalculated based on the selected fit method.