search for: dingjun_cn

Hi, everyone, Is there a way to get the detailed variable descriptions of a built-in dataset? By using attributes(Boston) I can get the names of each variables of a builtin dataset 'Boston'(in package "MASS"), but I don't know what each variable means. Can some body tell me how I can get more detailed information about each variable? Thank you! Jun

Hi Everyone, I just don't know how to extract the information I want from the summary of a linear regression model fitting. For example, I fit the following simple linear regression model: results = lm(y_var ~ x_var) summary(results) gives me: Call: lm(formula = y_var ~ x_var) Residuals: Min 1Q Median 3Q Max -5.9859 -1.5849 0.4574 2.0163 4.6015 Coefficients:

Hi, I am just wondering if there is an easy way to count in a numeric vector how many numbers don't have replicates. For example, a=c(1,1,2,2,3,4,5), how can I know there are three numbers (3, 4 and 5) without replicates? Thank you! Jun =====

Hi, everyone, I have a question regarding function cv.glm in library 'boot'. Basically cv.glm can calculate the estimated K-fold cross-validation prediction error for generalized linear models. My question is this: if I am fitting a logit model, what kind of threshold will it use to calculate the prediction error (saved in 'delta')? It will use 0.5 as the threshold or pick a

Hi Everyone, I am doing hierarchical clustering analysis and have a question regarding "cutree". I am doing things like this: hc <- hclust(dist(X)) a <- cutree(hc, k=2) Basically "a" is a vector containing the assignments of 1 or 2 for each sample. May I know how "cutree" decides to assign 1 and 2's to each sample (in other words, how clusters 1 and 2

Hi All, In function "rgb", alpha parameter is supposed to set the transparency value. But in my following two examples, it didn't work: plot(1,col = rgb(1,0,0,alpha =0.8)) # as long as alpha < 1, there is no point in the plot. plot(1,col = rgb(0,0,255, alpha=254, maxColorValue=255)) # as long as alpha < 255, there is no point in the plot. Do I use it in the right way? Any

Dear R users, I have a question regarding how to make row labels readable in a heat map. I have successfully made a heat map using function "heatmap.2" in the package "gplots". However, as there are many rows in the heat map, I have difficulties labeling them (heatmap.2 provides a parameter "labRow" to label the row names, but as I have too many rows, I can not make

Hi Everyone, Recently I got puzzled by the function read.table, even though I have used it for a long time. I have such a file (tmp.txt, 2 rows and 3 columns, with a space among columns): 1 2'-PDE 4 2 3'-PDE 5 if I do: a = read.table("tmp.txt", header = F, quote = "") a V1 V2 V3 1 1 2'-PDE 4 2 2 3'-PDE 5 Everything is fine. However, if I do: a