A researcher administered four different self-report questionnaires designed to measure trait resilience to a group of participants on two separate occasions, three weeks apart, to evaluate test-retest reliability.
| Questionnaire | Mean from Test 1 | Mean from Test 2 |
|---|---|---|
| Scale W | 62.4 | 61.9 |
| Scale X | 28.1 | 23.4 |
| Scale Y | 45.3 | 59.8 |
| Scale Z | 19.5 | 38.2 |
Using the data in Table 1, which scale has the lowest level of external reliability?
Scale W
Scale X
Scale Y
Scale Z
