Copyright: TSLRTable and TSLRQuery Copyright © 1997, AAS Inc.


TSLRegress

TSLRegress	Series

Add Regression Capabilities to Delphi Apps

Without Statistical Programming

It's now easier than ever to analyze data stored in Borland Database Engine native format tables.  Exporting data from Delphi database systems to Excel, Quattro Pro, or SPSS for simple linear regression analysis is no longer necessary.

Today's businesses collect numerous quantites of data related to their customers, products, marketing, and manufacturing processes.  In fact, the majority of applications developed in Delphi are, in part, database applications.

Many data gathered by organizations exhibit a variety of suspected or unknown mathematical trends between the data fields.  Linear regression allows those who collect and evaluate data to fit equations to the dataset in order to

   summarize and condense a data set to obtain predictive formulas

   confirm or reject a proposed mathematical relationship

   assist in the search for a mathematical relationship

   perform quantitative comparisons of two or more data sets

Use of the linear regression component set assumes that the end user understands the mathematical model and can correctly interpret the output, or that the developer understands the output of a regression model, and can include an interpretive analysis in his/her user interface.

Regression Model and Output

The Predict function for each of the SLR components computes all attributes of the regression and returns the predicted paired y-value for an arbitrary value of x, according to the model

Each of the following methods and properties are available to the developer (who can make them available to the end-user as necessary):

Methods

 LoadValues

 Predict

 ShowPlots

Properties

 b0	 b1	 ControlVarField

 DegreesOfFreedom	 e	 ResponseVarField

 rSquared	 SSE	 SSR

 SST	 syx	 t

 x	 xBar	 xMax

 xMin	 y	 yBar

 yHat	 yMax	 yMin

 TSLRTable

The TSLRTable includes all the functionality of the TTable included in the Delphi VCL for accessing tables through the Borland Database Engine.  In addition, the methods and properties described above define a complete linear regression between two datafields identified in the ControlVarField and ResponseVarField properties.  The values of the ControlVarField and ResponseVarField properties are specified by the developer or (through developer's code) by the user.  Any two numerical fields in a database table can be used to perform the regression and analysis.

The regression uses all data in the attached table.  The SetRange methods can be used on indexed tables to use a subset of the data; however, the TSLRQuery component is highly recommended for this purpose.

 TSLRQuery

The TSLRQuery includes all the functionality of the TQuery included in the Delphi VCL for accessing tables through the Borland Database Engine.  Like the TSLRTable components, each of the above methods and properties are available to developer/user and properties of the TSLRQuery define a complete linear regression between two datafields (ControlVarField and ResponseVarField properties).  Any two numerical fields in a database table can be used to perform the regression analysis.  The actual SQL query defines the records returned in the live data set; these are the records included in the regression.

The TSLRQuery is useful for performing regression on subsets of the data.  For example, a sporting goods retailer might want to look at the relationship between daily sales and temperature during March, April and May.  Setting the ControlVarField property to temperature and the ResponseVarField property to daily sales, the SQL may look something like

Select * from "customer.db"

Where season = 'spring'

Only spring sales are returned in this dataset.  The user could then view, plot and perform other analyses on this output using the Plot and/or Predict functions.

View of the Data

Of great value in most statistical analyses is a look at the visual relationships among data.  The x,y,e, and fitted-y properties allow the user to plot the relationships between the (x,y) pairs and the residual values.  Any charting program available to the user can be used; however, TSLRegress components include a plotting module to allow the user to view these outputs using only a single line of code (e.g., SLRTable1.ShowPlots;).

Viewing the data may serve as a basis for further analysis using other statistical analysis software, or confirm or reject the need for further analysis.

The SLR components include a plotting facility to allow graphing of scatter

plots, fitted equations, confidence bands, and residuals.

TSLRegress Components

16-Bit and 32-Bit versions included

Unlimited Runtime Distribution

Product	Cost	User(s)
Single: TSLRTable and  TSLRQuery	$39.00	Single Application Developer
Multiple: TSLRTable and  TSLRQuery	$39.00 First copy. 25% discount on each additional copy.	For two or more developers at a single location

Contact

Applied Analytic Systems, Inc

Carnegie Office Park

600 North Bell Ave

Bldg. 1, Suite 112

Carnegie,  PA  15106

Phone: 412.278.2360

FAX: 412.788.4205

All prices in US dollars. TSLRegress Copyright  © 1997 Applied Analytic Systems Inc.   Delphi is a registered trademark of Borland International, Inc.  Excel is a trademark of Microsoft Corporation.  Quattro Pro is a trademark of Corel Corporation.  SPSS is a trademark of SPSS Inc.