search for: coefffici

...rdering of the levels? I am confused about the fact, that coefficients for different levels are calculated, depending on weather i include level 0 or not: If level 0 is included, with both contrasts coxph calculates coefficients for group 1 ... group 5. But if i exclude level 0, coxph calculates coeffficients for group 2 ... 5 with treatment and coefficients for group 1 ... 4 using helmert: > options(contrasts = c("contr.treatment", "contr.poly")) > cox.t <- coxph(Surv(time,cens) ~ as.factor(group), data=data) > options(contrasts = c("contr.helmert", &qu...

...y(t-k) like an ordinary correlation coefficient. ACF is the simple ( i.e. unconditional ) correlation between a time series and it's lags thus y(t)=a+b*y(t-k) gnerates the kth autocoreelation coefficient (b). If we have form y(t)=a+b*y(t-1)+c*y(t-2) .. then (c) is the PARTIAL AUTOCORRELATION COEFFFICIENT or in other words the CONDITIONAL CORRELATION of lag 2 given lag1 PACF(k) estimates the correlation between y(t) and y(t-k) adjusted for the effects of y(t-1), ..., y(t-k+1). Model identification is achieved by looking at the pattern of the ACF and PACF. - If the ACF dies off exponentially, but...

Hello! I work with : R : Copyright 2006, The R Foundation for Statistical Computing Version 2.3.1 (2006-06-01) On Windows XP Professional (Version 2002) SP2. At this moment I use the function "nls" combined with a selfStar model (SSmicmen, related to Michaelis-Menten equation, and provided by the "stats" package). When I realise the following operation (cf. p 59 of the