| | Confidence Interval (C.I.) on difference between two proportions |
| | Treadmill | | | | | | Exercise Bike |
| | p1 | 0.1678832117 | | | | | p2 | 0.4967320261 | | | Formulas are highlighted |
| | q1 | 0.8321167883 | | | | | q2 | 0.5032679739 |
| | n1 | 137 | | | | | n2 | 153 |
| | Service contract | 23 | | | | | Service contract | 76 |
| | zc | 1.96 | 95% Confidence Level | | | | zc | 1.96 |
| | sigma(p1) | 0.0625880707 | | | | | sigma(p2) | 0.0792266119 |
| | 0.105295141 | <= | p1 | <= | 0.2304712824 | | 0.4175054142 | <= | p2 | <= | 0.575958638 |
| | | Sigma(p1-p2) | | 0.1009659478 |
| | | Proportion difference | | -0.3288488145 |
| | | Confidence Interval | | Min | max |
| | | | | -0.4298147623 | -0.2278828666 |
| | About: One Proportion confidence intervals: http://sphweb.bumc.bu.edu/otlt/MPH-Modules/QuantCore/PH717_ConfidenceIntervals-OneSample/PH717_ConfidenceIntervals-OneSample5.html |
| | Confidence interval calculators: http://vassarstats.net/prop1.html |