File Coverage

blib/lib/Statistics/PointEstimation.pm

Criterion	Covered	Total	%
statement	90	116	77.5
branch	13	34	38.2
condition	4	15	26.6
subroutine	17	21	80.9
pod	0	6	0.0
total	124	192	64.5

package Statistics::PointEstimation;
use strict;
use Carp;
use vars qw($VERSION @ISA $AUTOLOAD);
use Statistics::Distributions qw(chisqrdistr tdistr fdistr udistr uprob chisqrprob tprob fprob);
use Statistics::Descriptive;
use POSIX;


@ISA= qw (Statistics::Descriptive::Full);
$VERSION = '1.1';
my %confidence_interval=  #data related to confidence interval
(

	"significance" => undef,
	"alpha" => undef,
	"df" =>undef,
	"standard_error" => undef,
	"t_value" =>undef,
	"t_statistic" =>undef,
	"t_prob" =>undef,
	"delta" =>undef,
	"upper_clm" => undef,
	"lower_clm" =>undef,
	"valid"  =>undef
);



sub new{
	my $proto = shift;
	my $class = ref($proto) || $proto;
	my $self = $class->SUPER::new();
	my %confidence=%confidence_interval;
	$self->{confidence}=\%confidence;
	bless ($self, $class);
	return $self;
}

sub compute_confidence_interval{
	my $self=shift;
	croak "sample size must be >1 to compute the confidence interval \n" if($self->count()<=1);
	$self->{'significance'}=95 if (!defined($self->{'significance'}));
	$self->{df}=$self->count()-1;
	$self->{alpha}=(100-$self->{significance})/2;
	$self->{alpha}/=100;
	$self->{standard_error}=$self->standard_deviation()/sqrt($self->count());
	$self->{t_value}=abs tdistr($self->{df},$self->{alpha});
	$self->{delta}=$self->{t_value}*$self->{standard_error};

	$self->{upper_clm}=$self->mean() +$self->{delta};
	$self->{lower_clm}=$self->mean() -$self->{delta};
	$self->{t_statistic}=$self->{standard_error}
						?($self->mean()/$self->{standard_error}):0;
	$self->{t_prob}=1- abs (tprob($self->{df},-1*$self->{t_statistic})-tprob($self->{df},$self->{t_statistic})) ;
	$self->{valid}=1;
	return 1;

}
sub add_data{
	my $self = shift;
	my $aref;

	if (ref $_[0] eq 'ARRAY') {
		$aref = $_[0];
	}
	else {
		$aref = \@_;
	}
	my $significance=$self->{'significance'} if (defined($self->{'significance'}));
	$self->SUPER::add_data($aref);
	$self->{'significance'}=$significance;
	$self->compute_confidence_interval() if ((defined($self->{count}))&&($self->{count}>1)) ;

	return 1;

}
sub set_significance{   # set the significance level. usually 90, 95 or 99
	my $self=shift;
	my $significance=shift;
	$self->{'significance'}=$significance if (($significance>0)&&($significance<100));
	$self->compute_confidence_interval() if((defined($self->{count}))&&($self->{count}>1));
	return 1;

}

sub print_confidence_interval{
	my $self=shift;
	print "mean:",$self->mean(),"\n";
	print "variance:",$self->variance(),"\n";
	my $confidence=\%confidence_interval;

	foreach my $k ( keys %$confidence)
	{
		print "$k:", $self->{$k}," \n";
	}
	return 1;

}

sub output_confidence_interval{
	my $self=shift;
	croak "sample size must be >1 to compute the confidence interval\n" if($self->{valid}!=1);
	my $title=shift;
	print "Summary  from the observed values of the sample $title:\n";
	print "\tsample size= ", $self->count()," , degree of freedom=", $self->df(), "\n";
	print "\tmean=", $self->mean()," , variance=", $self->variance(),"\n";
	print "\tstandard deviation=", $self->standard_deviation()," , standard error=", $self->standard_error(),"\n";
	print "\t the estimate of the mean is ", $self->mean()," +/- ",$self->delta(),"\n\t",
		" or (",$self->lower_clm()," to ",$self->upper_clm," ) with ",$self->significance," % of confidence\n";
	print "\t t-statistic=T=",$self->t_statistic()," , Prob >|T|=",$self->t_prob(),"\n";
}

sub AUTOLOAD{
	my $self = shift;
	my $type = ref($self)
	or croak "$self is not an object";
	my $name = $AUTOLOAD;
	$self->{_confidence}=\%confidence_interval;
	$name =~ s/.*://;
	return if $name eq "DESTROY";
	if (exists $self->{_permitted}->{$name} ) {
		return $self->{$name};
	}
	elsif(exists $self->{'_confidence'}->{$name})
	{
		return $self->{$name};
	}
	else
	{
		croak "Can't access `$name' field in class $type";
	}
}
1;

package Statistics::PointEstimation::Sufficient;
use strict;
use Carp;
use vars qw($VERSION $AUTOLOAD @ISA);
use POSIX;
@ISA=qw (Statistics::PointEstimation);
$VERSION='1.1';
my %fields=  #data related to confidence interval
(
        "count"=>undef,
        "mean" =>undef,
        "variance" => undef,
        "standard_deviation" =>undef,
        "significance" => undef,
        "alpha" => undef,
        "df" =>undef,
        "standard_error" => undef,
        "t_value" =>undef,
        "t_statistic" =>undef,
        "t_prob" =>undef,
        "delta" =>undef,
        "upper_clm" => undef,
        "lower_clm" =>undef,
        "valid"  =>undef
);

sub new{
        my $proto = shift;
        my $class = ref($proto) || $proto;
        my $self = {%fields};
        bless ($self, $class);
        return $self;
}
sub add_data{

     croak "the add_data() method is not supported in Statistics::PointEstimation::Sufficient\n";

}
sub load_data{
        my $self=shift;
        my ($count,$mean,$variance)=@_;
        $self->{count}=$count;
        $self->{mean}=$mean;
        $self->{variance}=$variance;
        $self->{standard_deviation}=sqrt($variance);
        $self->compute_confidence_interval() if ($self->count()>1) ;
        return;

}

sub AUTOLOAD{
        my $self = shift;
        my $type = ref($self)
        or croak "$self is not an object";
        $self->{_confidence}=\%fields;
        my $name = $AUTOLOAD;
        $name =~ s/.*://;
        return if $name eq "DESTROY";

        if(exists $self->{_confidence}->{$name})
        {
                return $self->{$name};
        }
        else
        {
                croak "Can't access `$name' field in class $type";
        }
}
1;


__END__