Hello people, I'd like to ask you some questions: 1-How can I introduce an intercept in arima.sim function? 2-How can I edit the initial values (=initial conditions) in arima.sim function? 3- How can I put my own x-axis in plot function? Ex: It could be a vector or array with same dimension of the plotted variable. 4-How can I augment grid values on y-axis or x-axis in plot function? Ex:Imagine that the gave grid is 10 by 10 and I would like the put it in 2 by 2 or 5 by 5. 5- Is it possible to introduce or to construct some kind of kernel on spectrum function? Ex: Parzen, Bartlet, etc.. Waiting for answers. http://www.ieg.com.br