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CD ROM Paradise Collection 4 1995 Nov.iso
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simst35.zip
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INSTALL._D2
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SIM2NL.SCR
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1994-08-25
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SET COLOR BLACK ON CYAN;
IF $MONO SET COLOR BLACK ON LIGHTGRAY;
CLS;
BOX
NONLIN 3.2
Nonlinear Regression and Curve Fitting
by Phillip H. Sherrod
Nonlin is a program for IBM PC computers that performs
linear and nonlinear statistical regression analysis
and curve fitting.
ENDBOX;
BOX;
Nonlin determines the values of parameters for an equation,
whose form you specify, that cause the equation to best fit
a set of data values. Nonlin can handle linear, polynomial,
multivariate, logistic, exponential, and general nonlinear
functions. You specify the form of the equation to be fitted
using normal algebraic notation. Nonlin can also plot the
data and fitted equation on the screen or an HP LaserJet
printer.
ENDBOX;
BOX;
For example, the following Nonlin commands fit a logistic
growth equation to data for the AIDS infection rate:
Title "Logistic Fit for AIDS Cases";
Variables year,newcases;
Parameters k1,a,b;
Function newcases = k1 / (1+exp(a+b*(year-1980)));
Plot grid;
ENDBOX;
BOX
For more complex analyses Nonlin provides programming
commands in its analysis language that include
conditional statements (if, else), looping (for, while),
work variables, and arrays. For example, the following
Nonlin commands fit a curve consisting of two lines with
a bend in the middle to some data values:
Title "Piecewise Linear Function";
Variables x,y;
Parameters b0,b1,b2;
Double pivot = 5;
If (x < pivot) {
Function y = b0 + b1 * (x - pivot);
} else {
Function y = b0 + b2 * (x - pivot);
}
Plot grid,rline;
ENDBOX;
BOX
A shareware version of Nonlin is available from most major
bulletin boards. The registered version of Nonlin comes
with a 60 page typeset manual that explains regression
analysis and gives many examples. The registered version
of the program is available for $45 ($50 if outside the
United States) and may be ordered from the author:
Phillip H. Sherrod
4410 Gerald Place
Nashville, TN 37205-3806 USA
615-292-2881
Internet: 76166.2640@compuserve.com
ENDBOX;
BOX
NONLIN can also be run from within SIMSTAT with the use
of SIM2NL, an addin program written by Normand Péladeau
and Phillip H. Sherrod. This addin program integrates
NONLIN into SIMSTAT providing to NONLIN users an windows
like interface with pulldown menus, context sensitive
help and mouse support. SIM2NL is sent free to all
registered users of SIMSTAT or NONLIN.
ENDBOX;
BOX
Further information about SIM2NL can be obtained
at the following addresses.
By mail: Normand Peladeau
Provalis Research
5000, Adam street
Montreal, QC
H1V 1W5
By Email: CompuServe: [71760,2103]
Internet: 71770.2103@compuserve.com
ENDBOX;