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Distribution Analyzer Software
Version 1.2 for Windows XP, Vista, 7, 8 and
10, including 64-bit versions.
What is Distribution Analyzer?
Distribution Analyzer is a shareware software
package for identifying a distribution that best fits a set of data and for
estimating expected ranges for future values. It provides a means of
performing Normal Tolerance Intervals (K-intervals) and Variables Sampling Plans
on data that does not fit the normal distribution. The analysis performed
Selection of Best Fit Distribution and Estimation of Parameters
Test of Whether Selected Distribution Adequately Fits the Data
Determination of a Transformation (Function) That Can be Applied to Data
so that Transformed Data Fits the Normal Distribution
Construction of Tolerance Intervals Including a Specified Percentage
of the Future Values (Normal Tolerance Interval)
Confidence Statements for Percentage of Future Values in Spec (Variables
Take an example of break force values show below. There is a lower spec
limit of 4 pounds:
An initial analysis of the data is shown below. By default, the normal
distribution is assumed. The best fit normal distribution is shown in blue
along with a histogram of the data. The Test of Fit indicates the normal
distribution does does not adequately fit this set of data.
Clicking the Find Best Distribution button, identifies the Largest Extreme
Value family of distributions as the best fit. The analysis for this
distribution is shown below. The Test of Fit passes, so the Largest
Extreme Value Distribution adequately fits the fit and can be used as the basis
of further analysis.
Having passed the Test of Fit, ranges for future values are provided.
First is the Tolerance Interval:
"With 95% confidence more than 99% of the values are
This is akin to the Normal Tolerance Interval or K-Interval but does not
The second is relative to the spec limits:
"With 95% confidence less than 0.0031% of the values
are out of spec."
This is akin to a variables sampling plan but does not assume normality.
Can quickly find the distribution that best fits
Includes the following basic distributions:
Exponential and Negative Exponential
Largest Extreme Value family:
Largest Extreme Value distribution
Negative Weibull distribution
Smallest Extreme Value family:
Smallest Extreme Value distribution
Negative Fréchet distribution
Gamma and Negative Gamma distributions
Johnson Family of distributions
Loglogistic and Negative Loglogistic
Lognormal and Negative Lognormal
Pearson Family of distributions
The above distributions include, as special
cases, Chi-Square, Erlangian, Fisk, Log Exponential.
In addition, log-distributions are included for
all the above distributions (log-Beta, log-Weibull, ...)
Fit Distributions Using Methods of Moments and
Maximum Likelihood (using restrictions that ensure data and spec limits are
within the range of bounded distributions).
Test whether distribution adequately fits the
Generate tolerance interval for future values and
confidence interval for percentage of future values in spec.
Generate random values for all the above
Display Skewness-Kurtosis plots to understand
relationships between distributions
Calculate probabilities and percentiles of the
Simple to use. Novice users can just enter
the data and click on at most 3 buttons. You don't have to be familiar
with all the distributions.
You don't have to know Greek. All
distributions are represented by their moments (average, standard deviation,
skewness, ...). It is easy to compare distributions and generate
random numbers from different distributions with the same mean, standard
deviation, skewness, etc.
Complete control. Advanced users can
specify distributions to use, specify bounds and parameters of the
distribution. You can see the parameters of the distribution as
moments or in Greek form.
Capabilities not found anywhere else
Confidence statements relative to the
percent in spec
Wider range of distributions than any other
Handles bounded distributions and bounds on
data to ensure meaningful results (the spec limits are always
within the range of the distribution).
Download Full Version of Software - You May Try it Free for 30 Days
version of the software can be downloaded below. After installing you can
use it for free for a 30-day trial. After 30 days, if
you want to continue using the software, you must purchase it at a
cost of US$275 ($297.69 for residents of Illinois). Click the button below to download
the installation program.
The file da12.exe will be downloaded. Running this file
will install the software on your system including the user manual.
Click below to just download and view the user
manual da12man.pdf. You must have a copy
of the free Adobe Acrobat Reader® to view the file.
To continue using the software after the 30-day trial period, you must
purchase the software at a cost of US$275 ($297.69 for residents of
Illinois). You can purchase the software using our
web store. Otherwise you can
purchase by Fax or mail using the
following order form. Also available
are site licenses.
A user name and registration code will be emailed to you allowing you to
continue using the software. You also get free upgrades for 1 year.