Use Parametric Distribution Analysis to fit a chosen distribution to your data and get estimates that describe the reliability of your product. Parametric distribution analysis estimates the parameters of the chosen distribution.

Based on the fitted distribution, you can:

·    Display parameter estimates and distribution characteristics such as mean time to failure (MTTF)

·    Estimate percentiles and survival probabilities

·    Compare the fitted distribution to a historical distribution or compare the distributions of two or more data sets

·    Display probability, survival, cumulative failure, and hazard plots

When your product fails in different ways, use a failure mode analysis to evaluate the impact of each type of failure on the overall reliability. Each failure mode is assumed to be independent and may be modeled by different distributions. By analyzing each failure mode individually, you can more easily prioritize your improvement efforts.

You can:

·    Assess the reliability of each failure mode

·    Assess overall product reliability

·    Assess the overall product reliability after removing a specific failure mode

Muffler Data: Single failure mode analysis

A company set the warranty of its new line of mufflers at 50,000 miles. The reliability group wants to assess the reliability of the new line of mufflers and estimate the proportion of warranty claims they can expect. The measurement of interest is the number of miles driven on that muffler when the warranty claim is made.

You performed a parametric analysis using a Weibull distribution to describe the data.

Pump Data: Multiple failure mode analysis

The same automobile manufacturer is also working with the supplier of their water pumps to improve their overall reliability. To determine how to focus the improvement effort, engineering has collected data on how and when water pumps fail.

You performed a parametric multiple failure mode analysis using lognormal distributions to model bearing failures and gasket failures.

Data: Muffler.MTW, WaterPump.MTW (available in the Sample Data folder).