3 Replies Latest reply: Feb 19, 2001 12:00 AM by FredKohlhepp

# Probablity plot

How do I plot a probablity graph, say,"%Failure Rate (FR)" vs. "time"; where FR is cumulative failure rate from say 0.000001% to 100%?
Thanks.
Homi.
• ###### Probablity plot
For such a range of failure rates, you may want to consider a log plot of the failure rates, i.e., plot time on the x-axis in the normal linear fashion, and plot the log(base 10) of the failure rate or cumulative failure rate (written as either a discrete summation of failures with sigma or an integral if you have established a function of the failure rate as a function of time).

If this doesn't help, post a sample of your data and it can easily be demonstrated. Hope this helps.
• ###### Probablity plot
Sharoden,
Thanks for reply. In a data form what I have is----t-50 {time for cumulative 50% of fails(say 5000 hrs.)}, and, sigma=0.45(say). I want to plot a Weibull plot {ie., cumulative %fails(from 0.0001% to 99.99%) vs. time (from 10hrs. to 1E5 hrs.)---is it possible to do this in mathcad or Axum6?
Thanks,
Anganit.