NAME
Statistics::Forecast


DESCRIPTION
This is an Oriented Object module that calculates a future value by using existing values. The new value is calculated by using linear regression.


SYNOPSIS
   use Statistics::Forecast;Create forecast object

   my $FCAST = new Statistics::Forecast("My Forecast Name");Add data

   $FCAST->{DataX} = \@Array_X;
   $FCAST->{DataY} = \@Array_Y;
   $FCAST->{NextX} = $NextX;Calculate the result

   $FCAST->calc;Get the result

   my $Result_Forecast = $FCAST->{ForecastY);


INTERNALS
The equation for Forecast is:

   a+bx, where 'x' is the predicted value and
       _    _
   a = y + bx   b = sum((x+x)(y-y))/sum(x-x)**2



METHODS
new

Receives a forecast name, only to remember and returns the blessed data structure as a Statistics::Forecast object. 
 my $FCAST = new Statistics::Forecast("My Forecast");
calc

Calculate and return the forecast value. 
 $FCAST->calc;
dump

Prints data for debuging propose. 
 $FCAST->dump;
SumX

Returns the sum of X values. 
 my $SumOfX = $FCAST->{SumX};
SumY

Returns the sum of Y values. 
 my $SumOfY = $FCAST->{SumY};
SumXX

Returns the sum of X**2 values. 
 my $SumOfXX = $FCAST->{SumXX};
SumXY

Returns the sum of X * Y values. 
 my $SumOfXY = $FCAST->{SumXY};
AvgX

Returns the average of X values. 
 my $AvgX = $FCAST->{AvgX};
AvgY

Returns the average of Y values. 
 my $AvgY = $FCAST->{AvgY};
N

Return the number of X values. 
 my $N = $FCAST->{N};




EXAMPLE
   use Statistics::Forecast;   my @Y = (1,3,7,12);
   my @X = (1,2,3,4);   my $FCAST = new Statistics::Forecast("My Forecast");   $FCAST->{DataX} = \@X;
   $FCAST->{DataY} = \@Y;
   $FCAST->{NextX} = 8;
   $FCAST->calc;   print "The Forecast ", $FCAST->{ForecastName};
   print " has the forecast value: ", $FCAST->{ForecastY}, "\n";



AUTHOR
This module was developed by Alex Falcao (alexjfalcao@hotmail.com) http://webmaster.brfic.com





STATUS OF THE MODULE
This is the first version and calculates forecast value.





VERSION
0.1





COPYRIGHT
This module is released for free public use under a GPL license.