

DataFit is a
science and engineering tool that simplifies the tasks of data plotting, regression
analysis (curve fitting) and statistical analysis. What sets DataFit apart from similar
curve fitting and regression programs is its ease of use. With the combination of the
intuitive interface, online help and wide range of features, it is a tool that is used
effectively by both beginners and experts. Click here to view sample
screen images.
Version 9.1 Main features include:
 Intuitive Graphical Interface – most curve
fitting and regression software packages take a programming type approach, meaning that
you tell the program what to do in a pseudocode programming language. This approach
forces you to remember many commands, and the proper command syntax. With DataFit, the
program is driven by a welldesigned graphical interface, which makes it much easier to
learn and use. Remember, the goal your are striving for is accurate regression analysis,
not learning a new proprietary programming language.
 Nongraphical execution – DataFit can also be
run nongraphically from other programs. Simply create a configuration template (either on
your own or through the interface), save it, and call DataFit from your program. You can
choose handshaking options, such as DDE (Dynamic Data Exchange), progress indicators, and
message box displays. Macros support parameterization, which allow you to quickly batch
process hundreds of datasets in a single run.
 Online help and "tooltip" text –
With context sensitive help and "tooltip" text, the answers to your questions
are always close by.
 Straightforward data entry – Data can be
entered by typing it into a standard spreadsheet interface, by importing it from ASCII
files created by other applications, or by cutting and pasting it from other Windows based
applications.
 ODBC Database Connectivity – Data can be
imported directly from any ODBC (Open Database Connectivity) data sources. These sources
include Microsoft Access, dBase, Excel, Oracle, Paradox, Visual FoxPro and SQL Server.
 Multivariate linear or nonlinear regression –
DataFit can solve linear and nonlinear regression models with up to 20 independent
variables.
 Variable Selection (Data Mining) – DataFit
includes Forward Selection, Backward Elimination, Stepwise Selection and Manual variable
selection modes to help determine which independent variables should be included in your
regression model. These features include checks to help identify multicollinearity between
predictor variables.
 Predefined regression models – there are
currently 298 twodimensional and 242 threedimensional nonlinear regression models
predefined in DataFit. The predefined nonlinear regression models are commonly used in
scientific, statistical and engineering applications.
 User defined regression models – If regression
models you need are not predefined in DataFit you can define them yourself. User defined
regression models can have up to 100 fitting parameters, or variables, and you can use
whatever variable names you want to use in your model without "declaring" them.
This makes defining your own regression model as simple as typing in the equation. You can
also assign rulebased initial estimates to the models so that the initial estimates
don’t need to be assigned each time you run a regression problem. An additional
feature is the ability to specify the analytical derivatives for user defined models
(optional).
 Robust solver – DataFit utilizes the
LevenbergMarquardt method with double precision to perform nonlinear regression.
 Various solution options – You can perform
linear OR nonlinear regression on one model at a time that you choose from a list, groups
of models (predefined model groups, or define your own), or all of the models available
with one mouse click. The predefined models are grouped together based on the number of
parameters and the general shape of their curves. If you continuously solve the same
models over and over, you can create your own group consisting of the models you choose.
 Automatic solution ranking  As regression models
are solved, they are sorted automatically according to the goodness of fit criteria you
specify (Residual Sum of Squares, Correlation Coefficient, DOF Adjusted Correlation
Coefficient or Standard Error). If you aren't an expert and aren't sure which equation you
should use to model your data, DataFit helps you make this decision.
 Solution Log – DataFit tracks each step in the
regression process and reports it to the user in the solution log. If a model fails to
solve, the solution log contains some diagnostics to help you figure out the problem.
 Detailed regression results – DataFit reports
the following information about each solved regression model automatically without
additional user action.
 Number of observations
 Number of missing observations
 Number of nonlinear iterations performed
 Sum of Residuals
 Average Residual
 Residual Sum of Squares
 Standard Error of the Estimate
 Coefficient of Multiple Determination (R2)
 Proportion of Variance Explained
 Adjusted coefficient of multiple determination (Ra2)
 DurbinWatson statistic
 Coefficient values, Standard Error, tratio and Prob(t)
 Confidence Intervals (68, 90, 95 and 99 percent levels)
 Variance Analysis (ANOVA)
 Data Table, including entered data, calculated data,
residual,
 percent error, minimum residual and maximum residual.
 Formattable regression model plots
 Formattable residual probability plots
 Formattable residual scatter plots
 Presentation quality plotting capability  Create
2D and 3D plots of equations, data and/or regression models easily. Each plot is
completely customizable, including fonts, ranges, line colors and styles, error bars,
visibility, etc. You can also graphically compare the results of different models and/or
data on the same plot window. Plots can be saved along with all of their customization, or
copied to the Windows clipboard for pasting into other applications. Plot templates can be
saved and applied to instantly give plots your own custom appearance.
 Data calculator (currently 2D only) Manipulate raw
data or regression models in a built in data calculator. The data calculator can perform
over 70 mathematical and statistical operations on curves, discreet data, or numbers. The
calculator can also perform some special functions, such as FFT's or creating a data table
based on an equation you type in.
 Excel and HTML export support – results and
data table creation can be exported in Excel native format or HTML table formats in
addition to delimited text format.
 Automatic source code generation  Export source
code to utilize a model of your choice in a program that you have written. You can export
selfdocumented code in either BASIC or C.
 Accuracy  The accuracy
of DataFit has been verified with the Statistical Reference Datasets Project of the National Institute of
Standards and Technology (NIST).
 Direct link to the Web – From the
DataFit interface, you can connect directly to Oakdale Engineering’s home page on the
web for product updates and technical support. You can also submit bug reports or
enhancement requests.
Don't take our word for it. Download a free fully featured 30 day
evaluation copy, which will enable you to completely evaluate the software's power,
performance and features. You can also order securely online.
Interested in a COM curve fitting
component (DLL) to easily add a curve fitting engine to your program? Take a look at DataFitX!
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