The results of a blinded study assessing the use of plasmaD-dimer levels for diagnosing deep venous thrombosis (DVT) inpatients hospitalized for stroke rehabilitation reported increasedaccuracy over the standard procedure involving ultrasound. To testthe claims of this research team, an independent researcherconducted a study to determine if there was a difference in theaccuracy of diagnosis for DVT between the two methods. The data inthe table below summarize the findings of this study.
| diagnostic test: | correctly diagnosed | not correctly diagnosed |
| Plasma D-dimer | 85 | 20 |
| Ultrasound | 72 | 38 |
Construct a 95% CI for p1 – p2, where group1 is the plasmaD-dimer and group2 is the ultrasound group.
