Can thiệp chỉ số: ước tính tác động của một can thiệp điều trị hoặc phòng ngừa được đưa ra bởi tỷ lệ số lượng những người có mức độ rủi ro phải thay đổi để ngăn chặn một cái chết quá sớm để tổng số nguy cơ. | only at specific times of observation for example at the time of medical examination. See also censoring. Statistics in Medicine 1996 15 283-92. Interval estimate See estimate. Interval estimation See estimation. Interval scale See measurement scale. Interval variable Synonym for continuous variable. Intervention index An estimate of the impact of a therapeutic or preventive intervention given by the ratio of the number of people whose risk level must change to prevent one premature death to the total number at risk. See also number needed to treat. Journal of Clinical Epidemiology 1992 45 21-9 Annals of Experimental Pediatrics 1987 6 435-8. Intervention study Synonym for clinical trial. Interviewer bias The bias that occurs in surveys of human populations because of the direct result of the action of the interviewer. This bias can arise for a variety of reasons including failure to contact the right people and systematic errors in recording the answers received from the respondent. Journal of Occupational Medicine 1992 34 265-71. Intraclass correlation The proportion of variance of an observation due to between-subject variability in the true scores of a measuring instrument. The correlation can for example be estimated from a study involving a number of raters rating a number of subjects on some variable of interest. Dunn G. 2004 Statistical Evaluation of Measurement Errors Arnold London. Intrinsically nonlinear See nonlinear model. Intrinsic error A term used most often in a clinical laboratory to describe the variability in results caused by the innate imprecision of each analytical step. International Journal of Cancer 2001 96 320-5. Inverse normal distribution A probability distribution that has been used to describe phenomena such as the length of time a particle remains in the blood maternity data and the length of stay in a hospital. Generally a distribution that is skewed to the right as shown in Figure 48. Chhikara R. S. and Folks J. L. 1989 The Inverse
