위험률의 변화점에 대한 비모수적 추정

Nonparametric estimation of hazard rates change-point

  • 정광모 ((609-735) 부산시 금정구 장전동 산30, 부산대학교 통계학과)
  • 발행 : 1998.03.01

초록

위험률 변화점모형에서 특별한 함수형이나 분포함수에 대한 가정을 하지 않는 일반적인 모형을 고려하였다. 이러한 모형은 지금까지 주로 다루어 왔던 상수항 위험률의 변화점모형뿐만 아니라 여러 유형의 변화점모형을 내포한다. 중도절단된 자료하에서 위험률 변화점에 관한 모수적 모형을 가정하지 않고 변화점 이전과 이후의 넬슨(Nelson) 누적위험함수 추정량의 기울기 차를 이용하여 추정량을 제안하고, 그의 점근적 성질을 규명한다. 붓스트랩 추정량의 일치성과 점근분포를 유도하고, 몇가지 분포함수의 경우에 몬테칼로 모의실험을 통해 제안된 방법의 경험적 성질을 살펴보았다. 또한, 심장병 이석환자의 생존시간 자료를 통해 변화점을 추정하고 추정량의 붓스트랩 분포를 구하였다.

The change of hazard rates at some unknown time point has been the interest of many statisticians. But it was restricted to the constant hazard rates which correspond to the exponential distribution. In this paper we generalize the change-point model in which any specific functional forms of hazard rates are net assumed. The assumed model includes various types of changes before and after the unknown time point. The Nelson estimator of cumulative hazard function is introduced. We estimate the change-point maximizing slope changes of Nelson estimator. Consistency and asymptotic distribution of bootstrap estimator are obtained using the martingale theory. Through a Monte Carlo study we check the performance of the proposed method. We also explain the proposed method using the Stanford Heart Transplant Data set.

키워드

참고문헌

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