Segregation Analysis of 79 Chuvash Families With Polycythemia Using the “A Priori” Method of Hogben18
| Size of Sibship . | No. of Sibships . | Total No. of Individuals . | No. of Affected Individuals . | Variance . | |
|---|---|---|---|---|---|
| . | . | . | Observed . | Expected . | . |
| 2 | 15 | 30 | 16 | 17.142 | 1.837 |
| 3 | 11 | 33 | 14 | 14.270 | 2.893 |
| 4 | 18 | 72 | 22 | 26.330 | 7.561 |
| 5 | 16 | 80 | 24 | 26.222 | 9.468 |
| 6 | 11 | 66 | 20 | 20.073 | 8.535 |
| 7 | 6 | 42 | 9 | 12.118 | 5.821 |
| 8 | 2 | 16 | 6 | 4.445 | 2.345 |
| Totals | 79 | 339 | 111 | 120.600 | 38.460 |
| SE = 6.202 | |||||
| Size of Sibship . | No. of Sibships . | Total No. of Individuals . | No. of Affected Individuals . | Variance . | |
|---|---|---|---|---|---|
| . | . | . | Observed . | Expected . | . |
| 2 | 15 | 30 | 16 | 17.142 | 1.837 |
| 3 | 11 | 33 | 14 | 14.270 | 2.893 |
| 4 | 18 | 72 | 22 | 26.330 | 7.561 |
| 5 | 16 | 80 | 24 | 26.222 | 9.468 |
| 6 | 11 | 66 | 20 | 20.073 | 8.535 |
| 7 | 6 | 42 | 9 | 12.118 | 5.821 |
| 8 | 2 | 16 | 6 | 4.445 | 2.345 |
| Totals | 79 | 339 | 111 | 120.600 | 38.460 |
| SE = 6.202 | |||||
The patients were members of 81 families, but in two families, the patient with polycythemia was the only child. The expected number of siblings with polycythemia was 120.6 compared with the observed number of 111. The difference between the expected and observed numbers of affected siblings of 9.6 was less than two times the standard error of the variance (<2 × 6.202), and the hypothesis of autosomal recessive inheritance was not rejected (χ2 = 2.33, df = 6, P > .8).