Weibull++ Example 8 - Non-Parametric Recurrent Event Data Analysis

Examples provided here are purely for illustrating software features and functionality.

Weibull++ Example 8 – Non-Parametric Recurrent Event Data Analysis

Download Example File for Version 10 (*.rsgz10) or Version 9 (*.rsr9)

Background

Repairs are tracked on automatic transmissions in a sample of 34 cars in a preproduction road test. The objective is to determine the mean cumulative number of repairs per car by 24,000 test miles (equivalently 5.5 x 24,000 = 132,000 customer miles).

Experiment and Data

(The data for this example appears on page 4 in Recurrent Events Data Analysis for Products Repairs, Disease Recurrences, and Other Applications, by Wayne B. Nelson, 2003.)

The data set shown in the following table consists of each car’s ID, its test mileage at each transmission repair and its latest observed mileage (marked with a +). The test was accelerated by a factor of 5.5.

Car ID Mileage (+ latest)
24 7068 26744+
26 28 13809+
27 48 1440 29834+
29 530 25660+
31 21762+
32 14235+
34 1388 21133+
35 21401+
98 21876+
107 5094
108 21691+
109 20890+
110 22486+
111 19321+
112 21585+
113 18676+
114 23520+
115 17955+
116 19507+
117 24177+
118 22854+
119 17844+
120 22637+
121 375 19607+
122 19403+
123 20997+
124 19175+
125 20425+
126 22149+
129 21144+
130 21237+
131 14281+
132 8250 21974+
133 19250 21888+

Analysis

Step 1: Add a non-parametric recurrent event data analysis (RDA) folio to an existing project by choosing Insert > Folios > Non-Parametric RDA.

Step 2: For each car, enter the mileage for the transmission repairs (F) and the latest observed mileage (E) into the data sheet, as shown next.

Figure 1: Non-parametric RDA folio with data entered.

Figure 2: Non-parametric RDA results.

Step 4: Plot the mean cumulative function on the plot sheet. From the plot, it can be estimated that the mean cumulative number of repairs per car by 24,000 test miles is 0.3 (represented on the y-axis), as shown next.

Figure 3: Mean Cumulative Function plot.