The objective of the study is to analyze menarcheal age using methods related with estimating menarcheal age. The data(785 cases)was collected in Seoul during July 1992 from 2nd high-school girls born in 1975. The result of the study was summarized as following :
1. The highest proportion of menarcheal occurrence in total subject was 13.0-13.4 age group(18 percent), 15 percent in 13.5-13.9 and in 14.0-14.4 age groups respectively. The lowest menarcheal age of subject was 8.75 years and the highest menarcheal age of the subject was 17.08 years. The distribution of menarcheal occurrence age fited to Gaussion curve, and curve parttern of cumulative experience rate was showed S type. The percentile of menarcheal age in the subject was as follows : 25th 12.75, 50th 13.50, 75th 14.25.
2. The mean menarcheal ages by the methods of menarcheal age grouping(method A : 0.1 class, B : 0.5 class, C : 1.0 class) were 13.47 in method A, 13.52 in method B and 13.53 in method C.
3. In the median menarcheal age by probit analysis, the xi values of regressing equation was transformed to lowest(method A), middle(method B) and highest point (method C) in each menarcheal age group. The median menarcheal age estimated by method A was 12.48 years and 12.99 in method B and 13.43 in method C. The median menarcheal age estmated by method C was close to mean menarcheal age than any other methods.
4. To estimate median menarcheal age from the target population attained menarche at lower rate by probit analysis, the menarcheal experience rate by age in total subject was transformed to 1.53 percent, 7.52 percent, 31.85 percent, 65.61 percent, 90.83 percent, 99.36 percent, 99.87 percent, 100.00 percent, and those values corresponded with menarcheal experience rate of upper limit in each age group(10, 11…16, 17) of the subject from 8 to 17 years of age. The estimated median menarcheal ages based on transforming values were 13.83, 13.83, 13.61, 13.52, 13.46, 13.40, 13.41 and 13.43 years respectively.
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