| Group 1: Reminder letter only |
6.5 |
2.18 |
13 |
|
|
| Group 2: Letter, plus enclosed $5 |
10.0 |
2.65 |
20 |
|
|
| Group 3: Letter, plus $5, plus hard copy questionnaire |
|
|
|
|
| Total |
23.0 |
3.72 |
46 |
|
| Responded by mail |
13.5 |
3.02 |
27 |
|
| Responded by telephone |
9.5 |
2.59 |
19 |
|
| Group 1 vs. Group 2 |
|
|
|
1.04 |
NS |
| Group 1 vs. Group 3 |
|
|
|
14.64 |
<0.001 |
| Group 2 vs. Group 3 |
|
|
|
8.10 |
<0.01 |
| Group 3 mail vs. Group 3 telephone |
|
|
|
1.10 |
NS |