Statistics::PointEstimation - Perl module for computing the confidence interval in parameter estimation with Student's T distribution
use Statistics::PointEstimation;
my @r=(); for($i=1;$i<=32;$i++) #generate a uniformly distributed sample with mean=5 {
$rand=rand(10); push @r,$rand; }
my $stat = new Statistics::PointEstimation; $stat->set_significance(95); #set the significance(confidence) level to 95% $stat->add_data(@r); $stat->output_confidence_interval(); #output summary $stat->print_confidence_interval(); #output the data hash related to confidence interval estimation
#the following is the same as $stat->output_confidence_interval(); print "Summary from the observed values of the sample:\n"; print "\tsample size= ", $stat->count()," , degree of freedom=", $stat->df(), "\n"; print "\tmean=", $stat->mean()," , variance=", $stat->variance(),"\n"; print "\tstandard deviation=", $stat->standard_deviation()," , standard error=", $stat->standard_error(),"\n"; print "\t the estimate of the mean is ", $stat->mean()," +/- ",$stat->delta(),"\n\t", " or (",$stat->lower_clm()," to ",$stat->upper_clm," ) with ",$stat->significance," % of confidence\n"; print "\t t-statistic=T=",$stat->t_statistic()," , Prob >|T|=",$stat->t_prob(),"\n";
This module is a subclass of Statistics::Descriptive::Full. It uses T-distribution for point estimation assuming the data is normally distributed or the sample size is sufficiently large. It overrides the add_data() method in Statistics::Descriptive to compute the confidence interval with the specified significance level (default is 95%). It also computes the t-statistic=T and Prob>|T| in case of hypothesis testing of paired T-tests.
Yun-Fang Juan , Yahoo! Inc. (yunfang@yahoo-inc.com)
Statistics::Descriptive Statistics::Distributions