PURPOSE
This tool can be used to estimate parameters for Weibull distribution with least squares method. Least squares method is more accurate than maximum likelihood estimation method for small samples when there are few censoring samples.
This tool can:
- Estimate parameters and standard errors for Weibull distribution.
- Create probability plot with confidence band.
- Add percentile lines in probability plot.
- Support right censored data.
INSTALLATION
Download the file WBLRRX.opx, and then drag-and-drop onto the Origin workspace. An icon will appear in the Apps Gallery window.
NOTE: This tool requires OriginPro.
OPERATION
- Click the Weibull Fit with Least Squares Method icon in the Apps Gallery window to open the dialog.
- In the dialog's Input tab, choose a column for time data in Time Range.
If there is right censored data, choose a column for Censor Range, and select a value to indicate right censored data from Censoring Value drop-down list.
- Set a value between 0 and 100 for Confidence Level(%) for Parameters.
Check Covariance Matrix check box to output covariance matrix of parameters.
Check Probability Plot check box to create probability plot with confidence band.
- Click OK button. A report sheet and a plot data sheet will be created.
- Double-click on the probability plot in the report sheet.
Click on the Add Percentile Lines button at the bottom right of the graph to open the Add Percentile Lines dialog.
You can specify percentile lines by Percent (%) or Time.
Click OK button to calculate the time or percent for the given value in the dialog. Two drop lines will be added to the graph.