Reliability HotWire: eMagazine for the Reliability Professional
Reliability HotWire

Issue 10, December 2001

Tool Tips
Where can I get information on the theory behind the calculations and analyses being performed in ReliaSoft applications?

In addition to the software User's Guide, ReliaSoft's standard software packages come with an additional reference text that explains the theory and background of the calculations being performed by the particular application. Many users have found these reference texts to be an invaluable tool for increasing their understanding of the concepts behind the reliability analyses they regularly perform. These texts can be purchased separately from the software. For ordering information, see

Additionally, ReliaSoft provides free online versions of some of these reference texts that can be accessed from ReliaSoft's reliability engineering resources Web site at These include:

How can I determine the confidence bounds on parameter estimates in Weibull++?  

Confidence bounds on parameter estimates in Weibull++ can be obtained through the Quick Calculation Pad (QCP). Once a data set has been entered and analyzed, open the QCP, go to the Confidence Bounds tab and select the type of confidence bounds you wish to display for the parameter estimates.

Confidence Bounds Tab of the Weibull++ QCP

Once you have selected the type of confidence bounds, go to the Parameter Bounds tab and click the Calculate Bounds button. This will display the parameter estimates as well as the selected confidence bounds.

Weibull++ QCP with Confidence Bounds on Parameter Estimates

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