Accelerated life testing is still a relatively new subject in reliability engineering, but it is starting to gain greater acceptance in the industry. Accelerated life testing is the process by which a product is forced to fail more quickly than it would have under normal use conditions. Forcing the product to fail more quickly reduces test time and still allows you to understand the life characteristics of the product. Conceptually, this is a wonderful idea, but there are still many concerns. How do I set up an accelerated life test? What are the benefits? How much will it cost and how much time/money will it save me? The answers to these questions are not simple and straightforward, but when is anything worth having easily accomplished?

Contour Plots and Confidence Bounds on Parameters
There are multiple ways to estimate the confidence bounds of the estimated parameters of a selected distribution. One possible method is the likelihood ratio (LR) method and contour plots. Conceptually, this method is a great deal simpler than that of the Fisher Matrix (FM), although that does not mean that the results are of any less value. In fact, the LR method is often preferred over the FM method in situations where there are smaller sample sizes.

• What are the differences between ALTA and Weibull++?

• When conducting a Likelihood Ratio Test in ALTA 6, what does the significance level represent?

• Using the Function Wizard in ALTA or Weibull++, how can you calculate the results of functions such as R(t=MTBF)?