NAME
Statistics::Forecast
DESCRIPTION
This is a 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 (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.