NEWS
  • NLREG has been selected as the "Editor"s Pick" by SoftSeek.

    link to softseek.com

  • NLREG is in use at hundreds of universities, laboratories, and government agencies around the world (over 20 countries). For a list of a few organizations using NLREG click here.

  • If you have categorical variables, you may want to use a Decision Tree to model your data. Check out the DTREG Decision Tree Builder.

  • You also should check out the News Rover program that automatically scans Usenet newsgroups, downloads messages of interest to you, decodes binary file attachments, reconstructs files split across multiple messages, and eliminates spam and duplicate files.

    NIST BoxBOD Dataset


       1: /*
       2:  * Statistical Reference Datasets  (Nonlinear Regression)
       3:  * Statistical Engineering Division
       4:  * National Institute of Standards and Technology
       5:  * http://www.nist.gov/itl/div898/strd/
       6:  *
       7:  * Dataset Name:  BoxBOD            (BoxBOD.dat)
       8:  * 
       9:  * Description:   These data are described in detail in Box, Hunter and
      10:  *                Hunter (1978).  The response variable is biochemical
      11:  *                oxygen demand (BOD) in mg/l, and the predictor
      12:  *                variable is incubation time in days.
      13:  * 
      14:  * Reference:     Box, G. P., W. G. Hunter, and J. S. Hunter (1978).
      15:  *                Statistics for Experimenters.  
      16:  *                New York, NY: Wiley, pp. 483-487.
      17:  * 
      18:  * Data:          1 Response  (y = biochemical oxygen demand)
      19:  *                1 Predictor (x = incubation time)
      20:  *                6 Observations
      21:  *                Higher Level of Difficulty
      22:  *                Observed Data
      23:  * 
      24:  * Model:         Exponential Class
      25:  *                2 Parameters (b1 and b2)
      26:  * 
      27:  *                y = b1*(1-exp[-b2*x])  +  e
      28:  * 
      29:  *           Starting values                  Certified Values
      30:  * 
      31:  *         Start 1     Start 2           Parameter     Standard Deviation
      32:  *   b1 =   1           100           2.1380940889E+02  1.2354515176E+01
      33:  *   b2 =   1             0.75        5.4723748542E-01  1.0455993237E-01
      34:  * 
      35:  * Residual Sum of Squares:                    1.1680088766E+03
      36:  * Residual Standard Deviation:                1.7088072423E+01
      37:  * Degrees of Freedom:                                4
      38:  * Number of Observations:                            6  
      39:  */
      40: Title "BoxBOD";
      41: Variables y,x;
      42: // Note: Using Start 2 starting parameter values.
      43: Parameter b1 = 100;
      44: Parameter b2 = 0.75;
      45: Function y = b1*(1-exp(-b2*x));
      46: Plot;
      47: Data;
    
    Beginning computation...
    Stopped due to: Relative function convergence.
    
    
       ----  Final Results  ----
    
    NLREG version 4.0
    Copyright (c) 1992-1997 Phillip H. Sherrod.  All rights reserved.
    This is a registered copy of NLREG that may not be redistributed.
    
    BoxBOD
    Number of observations = 6
    Maximum allowed number of iterations = 500
    Convergence tolerance factor = 1.000000E-010
    Stopped due to: Relative function convergence.
    Number of iterations performed = 9
    Final sum of squared deviations = 1.1680089E+003
    Final sum of deviations = 8.2065627E+000
    Standard error of estimate = 17.0881
    Average deviation = 12.1533
    Maximum deviation for any observation = 23.4056
    Proportion of variance explained (R^2) = 0.8805  (88.05%)
    Adjusted coefficient of multiple determination (Ra^2) = 0.8506  (85.06%)
    Durbin-Watson test for autocorrelation = 1.269
    
    
                 ----  Descriptive Statistics for Variables  ----
    
     Variable    Minimum value   Maximum value    Mean value     Standard dev.
    ----------  --------------  --------------  --------------  --------------
             y             109             224           172.5        44.20747
             x               1              10        4.666667        3.386247
    
    
                       ----  Calculated Parameter Values  ----
    
     Parameter  Initial guess   Final estimate   Standard error      t      Prob(t)
    ----------  -------------  ----------------  --------------  ---------  -------
            b1            100        213.809409        12.35452      17.31  0.00007
            b2           0.75        0.54723748       0.1045599       5.23  0.00637
    
    
                      ----  Analysis of Variance  ----
    
      Source     DF   Sum of Squares    Mean Square    F value   Prob(F)
    ----------  ----  --------------  --------------  ---------  -------
    Regression     1        8603.491        8603.491      29.46  0.00559
    Error          4        1168.009        292.0022
    Total          5          9771.5
    



    Return to NLREG home page

    Download demonstration copy of NLREG.

    Download manuals for NLREG.

    Purchase NLREG.

    DTREG Decision Tree building software.