v0.2.0

Added

• NormalDistribution::Model#confidence_interval now returns an instance of NormalDistribution::ConfidenceInterval
• NormalDistribution::ConfidenceInterval#include? provides easier access to comparison of a value to the confidence interval
• NormalDistribution::ConfidenceInterval implements attribute readers #lower_bound and #upper_bound to satisfy need for raw values of the bounds

Removed

• NormalDistribution::Model#confidence_interval does not return an instance of Array anymore