YBATH is a Windows based probability plotting software by Bathtub Software Inc. for analyzing multi-failure mode data used for making reliability improvements. It operates in a Windows 95, Windows NT, or Windows 2000 environment as a 32-bit program using long file names. For details about each YBATH revision, see the bottom of this page when considering upgrades for YBATH software. Price list for the software also provide for volume discounts.
Announcement:
Bathtub Software is pleased to announce its sale to Fulton Findings effective
Beginning with SuperSMITH version 4.0WE, YBATH is bundled as part of the SuperSMITH program and is available at no extra cost.
You can download the YBATH no-cost demonstration program from this website. You can use the authentic datasets included with the program to demonstrate the capabilities of the software. However, if you enter your own data into the program, the demonstration program will randomize the raw data. You can convert the demonstration program to a full strength program by purchasing an electronic key from Barringer & Associates, Inc using your credit card at the listed prices.
YBATH software will analyze Weibull mixtures of data for:
1)
2-parameter (b and h) or 3-parameter (b, h, and t0) Weibull distributions (see the 3-parameter minimum life
shift plot below),
2)
competing risks for a homogeneous population with two failure modes (see
the 4-parameter competing risk plot below),
3)
simple mixtures with two Weibull distributions that do not have
competing risks,
4)
competing risk mixtures for a subpopulations with an additional failure
mode (see the 5 parameter competing risk plot below), and
5)
compound competing risk mixture for elements of the traditional bathtub
curve (see the 7-parameter Weibull plot below).
More details and examples of these mixtures are described at the Bathtub
Software website. These complex analysis
methods require many more data points than for traditional Weibull
analysis. You can also download a brief
SAE paper on mixture analysis written by Carl Tarum from http://www.delphi.com/pdf/techpapers/1999-01-0055.PDF.
Here is an example of a 50 data point set of mixed failure data (yes, you need at least 20 data points for a 3-parameter plot and maybe 50 data points--or more--for a 7-parameter plot). The same data is used for each plot--notice the poor fit with only a few parameters and how well the trend lines fit the 7-parameter plots. These plots were made from the 7PAR.YBD file supplied with the YBATH program. Notice the deterioration in r^2, the coefficient of determination, using the same data but different analysis techniques for this data set containing a mixture of data with infant mortality, chance failures, and old age wear out. Remember it is always better to segregate your data based on physical evidence than to rely on software to untangle the mixture.
Age-to-failure and strength data from field or laboratory tests are quickly
plotted into trend lines to create order from random failure events. Weibull
probability plots are available. Age/time corrections can be computed
automatically to correct probability plot curvature when the age/time origin is
not zero.
Specific features of the YBATH program are:
·
YBATH helps analyze data with:
A single population but two independent
failure modes,
A mixed population with one sub-population
having a second failure mode (infant mortality)
A mixed population with on sub-population
have two failure modes and the other population
having
a third failure mode
Theory and equations behind this analysis is explained in the HELP file.
·
100's of data can be displayed and YBATH is menu driven for a short
learning period of 1/2 to 1 hour to enter the first data set and make a print
output data for "X" values of age to failure can be imported or
cut-and-pasted from an Excel spreadsheet
·
Suspended data is easily by use of a "Minus" value for age
·
Number of suspended and non-suspended data points is limited
·
Cumulative distribution function plots (i.e., unreliability) are simple
to obtain
·
Only 4 to 7 data
points needed to perform a minimum analysis--20 or more data points are
required with 3-4 data points from each distribution are more
reasonable--perhaps 50 to 60 data points may be helpful for tri-Weibull
analysis
·
Some overlap exists between WinSMITH Weibull (WSW) and YBATH
software--WSW works well on single and dual Weibull distributions whereas YBATH
works better on the more complicated analysis of tri-Weibull distributions.
·
2-parameter Weibull plots are available
·
3-parameter Weibull plots with zero shift of the time origin can be
chosen
·
4-parameter Weibull plots for competing risk can be chosen
·
5-parameter Weibull plots for competing risk mixtures can be chosen
·
7-parameter Weibath plots can be chosen
·
Rank regression or maximum likelihood parameter analysis can be
selected
·
Monte Carlo generated data can not be
plotted on the screen but can be displayed only in tabular format
·
Icons go directly from WinSMITH Weibull and WinSMITH Visual software
from Fulton Fulton
·
YBATH does not yet handle multiple data sets, confidence limits,
Kaplan-Meier, MLE contour plots, or Fisher Matrices and for these features
consider the use of WinSMITH Weibull software
·
Help File Hyperlinkes for:
First
Time Users
Data
Window
Macro
Window
Monte
Carlo Window
lot
Window
Weibull
Theory
Exit
Codes, Errors, Warnings, and Fixing Errors
Tips
and Additional information
How
Do I...
The price for YBATH is US $ 380.00 plus handling/shipping charges:
US $20 handling charge for USA Airborne
Express second day delivery,
US $40.00+ for Airborne Express deliveries
(with duties payable on your end)
Taxes for sales in
Terms are net 10 days for purchase orders.
See SuperSMITH Plus for discounts
and other pricing details.
Order YBATH by purchase order,
Visa/Master/American Express card, or by sending a check to the address shown
on the home page of this web site.
The New Weibull Handbook--Fourth Edition published by Dr. Robert B. Abernethy (US$88.00 +
shipping/handling) shows how concepts used for designing this software can help
in solving practical problems.
YBATH
REVISION HISTORY:
(From Current To Oldest
Revision) Revision details for YBATH
comes from the software help file under
the hyperlink “What’s New”
Version -Date
1.2.5
Program sold to Fulton
Findings. No change in
algorithms or data, but reference updated in program and help file to
reflect change of ownership
Return to top of page
1.2.4 -09 Nov 2001
-Now a 32 bit version, supporting long filenames.
-Main program is a Demo, registration can be added to
make a full strength version.
-Order of beta, eta, and t0 changed to match WinSMITH
results.
-Changed "p" to "u" to avoid confusion with p-values in
WinSMITH
-Additional plot features:
-
Mixture lines added on plot
-
Plot copy routine fixed to include parameter box
-
Fixed small bugs that generated nuisance errors
-
Can now plot data prior to solving.
-Removed
redundant dialog boxes, and upgraded help options.
-Improved
WinSMITH file open routine.
-Improved
(speed, accuracy) for 3-parameter Weibull routine
-Added
Benard's approximation and made default for ranks
1.2.3 -
-Added Benard's
approximation for ranks.
-Made Benard's approximation the default ranking
method.
-Beta Binomial Median ranks are now optional method
-New algorithm for 3 parameter Weibull.
-Added warning for 3 parameter non-convergence.
1.2.3 -24 Sep 2001 [Evaluation
Program—Not Sold]
-Fixed version number
(1.02.01 is same as 1.2.1 to VisualBasic)
-Fixed WinSMITH file open routine
-Added Help button to dialog boxes when iteration ends
-For data files, parameter boxes change to the best fit solved so far.
-Allowed plotting before data analysis.
-Removed redundant dialog boxes ("Solve this fit again?", and
"1. Normal Exit")
-Fixed Overflow message in Draw Line Routine.
1.02.01-23 July 2001 [Evaluation
Program—Not Sold]
-Upgraded program to 32-bit
version. (Long file names, Active X controls, etc.)
-Changed Options - Show Errors to False by default. This means that YBath
will not display minor errors that it can recover from.
-Added Demo option so program can be used in Demo mode.
-Changed portion defective nomenclature from "p" to "u" to
avoid confusion with p-values used in WinSMITH.
-Fixed bug that generated error when plot window was minimized.
-Added right-click menu item to Data window for ease in cut/copy/paste
-Added registry items for ease in access from other programs.
-Added Mixture lines on plot.
-Fixed plot Copy routine to include parameter box.
-Fixed print routine to print properly.
-Updated ccc calculations
for 2and 3 parameter Weibull per SAE paper
-Changed order of b, h on grids to match WinSMITH format. (Data file format did not change.)
1.0B -13 Dec 1997
-Fixed bug that generated
error when called from WinSMITH
-Added Plot button to Data Window
-Added warning if printing a plot for a fit that is only an estimate.
-Replaced text buttons with Icons on Data Window
-Improved grid editing features.
-Added additional information to help file.
-Added Context help so {F1} key will call an appropriate topic.- This eliminated "Help Topic not found" errors.
-Changed Initial estimate method for
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1.0A -
-Fixed Help Calls (Had call
to a non-existent file)
-Fixed math error that caused poor initial estimates for 5 parameter fits.
-Improved grid editing features
-Added Exit warning if print orientation changed.
-Added logic to allow custom Y data that may not be median ranks.
-Added fit and status line to Parameter Grid
-Improved plot format (Color, parameter grid)
-Improved plot print routine - Print Setup and Auto Redraw handled
automatically.
-Print setup includes standard page formats
-Added time display and confirm breaks in
-Original Release of YBath™. Program has
Macro,
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