Exponential Distribution Auto Batch Run Example

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This example appears in the Life Data Analysis Reference book.


A number of leukemia patients were treated with either drug 6MP or a placebo, and the times in weeks until cancer symptoms returned were recorded. Analyze each treatment separately [21, p.175].


Table - Leukemia Treatment Results
Time (weeks) Number of Patients Treament Comments
1 2 placebo
2 2 placebo
3 1 placebo
4 2 placebo
5 2 placebo
6 4 6MP 3 patients completed
7 1 6MP
8 4 placebo
9 1 6MP Not completed
10 2 6MP 1 patient completed
11 2 placebo
11 1 6MP Not completed
12 2 placebo
13 1 6MP
15 1 placebo
16 1 6MP
17 1 placebo
17 1 6MP Not completed
19 1 6MP Not completed
20 1 6MP Not completed
22 1 placebo
22 1 6MP
23 1 placebo
23 1 6MP
25 1 6MP Not completed
32 2 6MP Not completed
34 1 6MP Not completed
35 1 6MP Not completed


Create a new Weibull++ standard folio that's configured for grouped times-to-failure data with suspensions. In the first column, enter the number of patients. Whenever there are uncompleted tests, enter the number of patients who completed the test separately from the number of patients who did not (e.g., if 4 patients had symptoms return after 6 weeks and only 3 of them completed the test, then enter 1 in one row and 3 in another). In the second column enter F if the patients completed the test and S if they didn't. In the third column enter the time, and in the fourth column (Subset ID) specify whether the 6MP drug or a placebo was used.


Exp Distribution Example 9 Data.png


Next, open the Batch Auto Run utility and select to separate the 6MP drug from the placebo, as shown next.


BARsheet.png


The software will create two data sheets, one for each subset ID, as shown next.


Exp Distribution Example 9 6MP Data.png
Exp Distribution Example 9 Placebo Data.png


Calculate both data sheets using the 2-parameter exponential distribution and the MLE analysis method, then insert an additional plot and select to show the analysis results for both data sheets on that plot, which will appear as shown next.


Exp Distribution Example Overlay Plot.png