A statistical analysis of the factors that determine the age at which babies start walking.

To clarify the factors that determine the age when walking begins, this study first applied contingency tables and the chi 2 test to the questionnaire-data answered by the parents of 395 children. Among twelve factors, those that were not independent of the age of first walking were the use of a walker (p less than 0.01), the frequency of being carried on the chest (p less than 0.05) and the age of the first enrollment at a day-care center (less than 0.05). Second, this study employed the "quantification method of the second type" to clarify what factors help babies start walking early and what others do not. The subjects were divided into two groups--W0 (early-walkers) and W1 (others)--, and this grouping was used as an external criterion. The order of the factors according to the range of category scores is as follows: (1) birth weight, (2) order of birth, (3) frequency of being carried on the chest, (4) season of birth, (5) use of a walker, (6) age of the first enrollment at a day-care center. These factors included those that were not independent of the age of first walking ((3), (5), (6)). Therefore, the factors that had a wider range seem to be important in determining the age when babies start walking.