Discussions
Solve problems, and share tips and tricks with other JMP users.
Hello,
The below is the test table I made.
According to the description: https://www.jmp.com/support/help/en/18.1/index.shtml#page/jmp/event-plot.shtml#ww1386833
It meas there are total 100 samples.
And exactly at 4 readings: 50, 100, 150 and 200, there are 25 new failures happened.
So the failure rate I expected will be:
50, 25%
100, 50%,
150, 75%
200,100%.
The markers in the Weibull plot are very different from the failure rate I expected.
For example, the first read point at time 50 has failure rate as ~13%.
Now I learned that this is because the life distribution is using the Midpoint estimate to do the plot and fit.
But I want to use the Kaplan-Meier estimate to plot the markers and fit weibull, which is more intuitive to my audience.
Is there a way to change that in JMP? I had no luck searching in the preference setting.
Thank you very much.
I am using JMP18.2 now.
Looks like a follow up to
Please have a look at Analyze/Survival:
As an alternative, you can use GraphBuilder. In the Summary Statistics menu you can find "Cumulative Percent" - which uses the Kaplan-Meier definition to calculate the probability. With a trick *), you can even use it for points [from]:
Please note:
for i/N, the last points has a probability of 1 ... and gets lost when probability scales are used on the Y axis - like in the plots in this post. This is why I submitted a wish to add alternative probability functions as an option in Graph Builder:
*)
Graph Builder(
Transform Column( "1", Formula( 1 ) ),
Size( 429, 272 ),
Show Control Panel( 0 ),
Summary Statistic( "Median" ),
Graph Spacing( 4 ),
Variables( X( :Start time ), Y( :"1"n ) ),
Elements(
Points( X, Y, Summary Statistic( "Cumulative Percent" ) ),
Line(
X,
Y,
Connection( "Step" ),
Summary Statistic( "Cumulative Percent" )
)
),
);