Table 2.
Ranges and Sample Sizes for Age Group Variables
| Age | Sample Size | ||||||
|---|---|---|---|---|---|---|---|
| Groups | Min | Mean | Max | Total | Twin 1 | Twin 2 | Female% |
| 2 | 45 | 56.86 | 70 | 4314 | 2153 | 2161 | 49.05% |
| 71 | 77.36 | 102 | 4731 | 2339 | 2392 | 58.93% | |
| 3 | 45 | 53.48 | 61 | 2981 | 1494 | 1487 | 49.41% |
| 62 | 68.62 | 74 | 2909 | 1437 | 1472 | 50.70% | |
| 75 | 79.98 | 102 | 3155 | 1561 | 1594 | 62.00% | |
| 4 | 45 | 52.47 | 59 | 2599 | 1296 | 1303 | 49.13% |
| 60 | 63.49 | 69 | 1715 | 857 | 858 | 48.92% | |
| 70 | 74.35 | 79 | 3292 | 1651 | 1641 | 56.41% | |
| 80 | 84.60 | 102 | 1439 | 688 | 751 | 64.70% | |
| Full Sample | 45 | 67.63 | 102 | 9,045 | 4492 | 4553 | 54.22% |
Note. Age ranges, descriptive statistics, and sample sizes for two-group, three-group and four-group age splits for DIF analyses. Two- and three-group splits based on sample age quantiles, while four-group based on approximately ten-year age bins. The 25th, 50th and 75 quantiles of the age distribution are 57.2, 70.7 and 76.0, respectively. Female% indicates what percentage of the full sample in each age bin is female.