Medical educators are investigating whether virtual reality (VR) simulation training improves surgical skill acquisition compared to traditional video demonstrations. A sample of surgical trainees was divided into two independent groups. Group 1 trained using a high-fidelity VR headset, while Group 2 trained by watching standard video demonstrations. All trainees were then assessed on a complex suturing task, where their performance was scored on a scale from 0 to 25 (with 0 representing poor precision and 25 representing master-level proficiency). Some of the data and corresponding ranks are recorded in the table below.
| VR Simulator Group | Video Demonstration Group | ||
|---|---|---|---|
| Suture Score | Rank | Suture Score | Rank |
| 11 | 5 | 4 | 1 |
| 15 | 8 | 5 | 2 |
| 18 | 10 | 7 | 3 |
| 20 | 11 | 9 | 4 |
| 22 | 13 | 12 | 6 |
| 24 | 14 | 14 | 7 |
| 25 | 15 | 17 | 9 |
| 21 | 12 |
Mann-Whitney U U\,U Formulas:
U=the smaller of U1 and U2U = \text{the smaller of } U_1 \text{ and } U_2U=the smaller of U1 and U2
Where:
U1=n1n2+n1(n1+1)2−∑R1 U_1 = n_1 n_2 + \frac{n_1(n_1 + 1)}{2} - \sum R_1 U1=n1n2+2n1(n1+1)−∑R1and
U2=n1n2+n2(n2+1)2−∑R2 U_2 = n_1 n_2 + \frac{n_2(n_2 + 1)}{2} - \sum R_2 U2=n1n2+2n2(n2+1)−∑R2Calculate the U U\,U value for the data collected in this study using the Mann-Whitney U U\,U formulas provided. Show your workings.
513 exam-style questions on OCR A Level Psychology Data recording, analysis and presentation. Each one has a worked solution and a mark scheme showing where the marks go.