http://pages.optimizely.com/rs/optimizely/images/stats_engine_technical_paper.pdf
https://help.optimizely.com/Analyze_Results/Difference_intervals_and_improvement_intervals
http://pages.optimizely.com/rs/optimizely/images/stats_engine_technical_paper.pdf
https://help.optimizely.com/Analyze_Results/Difference_intervals_and_improvement_intervals
Test&Target_reporting_calculations
https://marketing.adobe.com/resources/help/en_US/tnt/pdf/Test&Target_reporting_calculations.pdf
complete_confidence_calculator
https://marketing.adobe.com/resources/help/en_US/target/target/complete_confidence_calculator.xlsx