Weibull++ Example 2 - Analyzing Complete Data

Background

Six units are tested to failure. The objective is to use the complete data from the analysis to obtain a probability plot with 90% 2-sided confidence bounds and a pdf plot.

Experiment and Data

The following times-to-failure are observed for the six units: 11,260; 12,080; 12,125; 12,825; 13,550 and 14,670 hr.

Analysis

Step 1: The parameters for the data are calculated using the normal distribution and rank regression on X as the parameter estimation method, as shown next.

Standard Folio with calculated parameters displayed

Step 2: Next, a probability plot is created with 90% 2-sided Type I (time) confidence bounds, as shown next.

Normal probability plot with 90% 2-side confidence bounds

Step 3: Finally, the pdf plot is created, as shown next.

Probability density function (pdf) plot for the analysis