tailieunhanh - MEDICAL STATISTICS - PART 10

Một kỹ thuật thống kê như cusum được sử dụng để so sánh những con số quan sát thấy trong một quá trình giám sát với các dữ liệu cơ bản. [Lancet năm 1995, 346, 196.] Khảo sát: Một cuộc điều tra thu thập thông tin lên kế hoạch từ các cá nhân về lịch sử, thói quen của họ | question asked as to whether an increase or decrease has occurred which can signal that something has changed the risk situation in the population of interest. A statistical technique such as the cusum is used to compare the observed numbers during a surveillance process with the baseline data. Lancet 1995 346 196. Survey An investigation that collects planned information from individuals about their history habits knowledge attitudes or behaviour. A health survey for example might include questions about smoking habits and exercise as well as a variety of demographic and socioeconomic characteristics. Hunt S. M. McEwan J. and McKenna S. P. 1986 Measuring Health Status Croom Helm London. Survival curve See survival function. Survival function The probability that the survival time of an individual is longer than some particular value. A plot of this probability against time is called a survival curve and is a useful component in the analysis of such data. See also product limit estimator and hazard function. Collett D. 2003 Modelling Survival Data in Medical Research 2nd edn Chapman and Hall CRC Boca Raton FL. Survival time Observations of the time until the occurrence of a particular event for example recovery improvement or death. Such data need special forms of analysis to deal with both possible skewness and censoring of the observations. See also Cox s proportional hazards model. Collett D. 2003 Modelling Survival Data in Medical Research 2nd edn Chapman and Hall CRC Boca Raton FL. Survivor function Synonym for survival function. Suspended rootogram Synonym for hanging rootogram. Switching effect The effect on estimates of treatment differences of patient s changing treatments in a clinical trial. Such changes of treatment are often allowed in for example cancer trials due to lack of efficacy and or disease progression. Statistics in Medicine 2005 24 1783-90. Symmetrical distribution A probability distribution or frequency distribution that is symmetrical .