View source for Comparing the Standard and Modified Gompertz Models

<noinclude>{{Banner RGA Examples}}
''This example appears in the [[Gompertz_Models|Reliability Growth and Repairable System Analysis Reference book]]''.
</noinclude>

Using the data in the following table, determine whether the standard Gompertz or modified Gompertz would be better suited for analyzing the given data.

{|border="1" align="center" style="border-collapse: collapse;" cellpadding="5" cellspacing="5"
|+'''Reliability Data'''
!Stage	
!Reliability (%)
|-
|0||	36
|-
|1||	38
|-
|2||	46
|-
|3||	58
|-
|4||	71
|-
|5||	80
|-
|6||	86
|-
|7||	88
|-
|8||	90
|-
|9||	91
|}

'''Solution'''
<br>
The standard Gompertz Reliability vs. Time plot is shown next.

[[Image:rga7.8.png|center|400px|Standard Gompertz Reliability vs. Time plot]]


The standard Gompertz seems to do a fairly good job of modeling the data. However, it appears that it is having difficulty modeling the S-shape of the data. The modified Gompertz Reliability vs. Time plot is shown next. As expected, the modified Gompertz does a much better job of handling the S-shape presented by the data and provides a better fit for this data.
 
[[Image:rga7.9.png|center|400px|Modified Gompertz Reliability vs. Time plot.]]