...one of the most highly
regarded and expertly designed C++ library projects in the
world.

— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards

boost::histogram::utility::deviation — Confidence level in units of deviations for intervals.

// In header: <boost/histogram/utility/binomial_proportion_interval.hpp> class deviation { public: // construct/copy/destruct explicit deviation(double) noexcept; // public member functions template<typename T> explicit operator T() const noexcept; operator confidence_level() const noexcept; };

Intervals become wider as the deviation value increases. The standard deviation corresponds to a value of 1 and corresponds to 68.3 % confidence level. The conversion between confidence level and deviations is based on a two-sided interval on the normal distribution.