search for: jjd9

Dear R users: I have run a logistic regression, used Gelman et al.'s car package to simulate the parameter estimates of that model, and have plotted the probability (using Gelman et al.'s invlogit() function) of the dependent variable being 1 given the value of a particular independent variable is at its mean. The plot has probabilities on the y-axis and the number (1-1000) of the

Hello: As someone making the move from STATA to R, I'm finding it difficult at times to perform basic tasks in R, so forgive me if I've missed an obvious and easily obtained solution to my problem. I've searched the help guides and the archives and have not been able to find a solution that works. I have a data frame with thousands of observations that looks something like this:

Hi: I've searched the archives and the Internet for hours but have yet to find a way to do stacked area plots (like the kind in Excel) in R. I think that polygon may work but it would require a bit of manipulation of my data. I was hoping for an easier way. An example of what I'm trying to do can be found here: http://jcharts.sourceforge.net/samples/stackedArea.html Thanks, Josip

Hello: I've come to a dead-end in my search for a solution to a graphing problem that I am encountering. I have used xyplot (from the lattice package) successfully to plot 36 time-series plots (lines) of under-5 mortality for a set of countries in Sub-Sarahan Africa. What I would now like to do is to add vertical bands (rectangles) that correspond to time-periods during which each of the 36

Dear R Helpers: I have a data set where the unit of observation is country-year. I would like to generate a new data set based on some inclusionary (exclusionary) criteria. Here is an example of the type of data that I have. df<-data.frame(cbind("country"=c(rep("Angola", 9), rep("Burundi", 7), rep("Chad", 13)), "year"=c(1975:1983, 1989:1995,

Dear R-users: Hello all: I'm having difficulty creating a new data frame, which would be a subset of an existing data frame, creaed by the random selection of subsets of observations based on different values of variables within the data frame. Here's an example of what my data frame looks like: fact x1 x2 x3 select... blue 23 2.2 1.1 1 blue 28 4.2 0.8 0 blue 34 2.8 0.9 0 ... red 43

Dear R Help-Listers: I have a problem that seems like it should have a simple solution, but I've spent hours on it (and searching the r-help archives) to no avail. What I'd like to do is to generate a new variable within a data frame, the values of which are dependent upon the values of an existing variable within that data frame. Assume that I have the following data:

Dear R-Helpers: I'm having a problem getting dates into the correct format. I have a data frame, which is based on a .csv file that I imported into R via read.table. R has converted my date variables to factors; when I use the as.Date command, most of the values are converted "correctly" (and by this I guess I mean converted "as I wish them to be") but some have not been.