my @values = $e->{lt};

##</code><code>##

my @values;
foreach my $e (@{$data->{httpSample}})
{
    push @values, $e->{lt};
    print "Lt_Value: ", $e->{lt}, "\n";
} 

##</code><code>##

use List::Util qw(min max sum);

print "Min Lt_Value: ", min(@values), "\n";
print "Max Lt_Value: ", max(@values), "\n";

if(@values) {
    print "Average Lt_Value: ", (sum(@values)/@values), "\n";
} else {
    print "No values so no average.\n";
}