search for: lisawang

...ot;for loop" and goes to "a[i]<-0". a<-b[s>3,] if (nrow(a)==0) ????????????? for (i in 1:nrow(a)){ a[i]<-1 } a[i]<-0 Lisa Wang Cancer Informatics, Ontario Cancer Institute/Princess Margaret Hospital, University Health Network; Email: lisawang at uhnres.utoronto.ca Phone: 416 946 4501 ext. 5201 Fax: 416 946 4619

Hello there, My name is Lisa and I'm doing analysis using genelized linear model-GEE model because I have some repeated measurements on the same patients (in a bilateral eye disease case). It would be very appreciated if you could shed some light on what function to use in R. Thank you very much Lisa Wang Msc. Toronto,Ca

Hello there, I am using R to plot some cumulative histogram for my data. Please help in this case. Thank you Lisa Wang Princess Margaret Hospital Toronto phone 416 946 4501 ext.4883

Hello there, I would like to do a Wilcoxon matched pairs signed rank sum test in R and tried the function wilcoxon.test. Is it in the "base" library? If not, please let me know which library it is in. Thank you in advance for your help Lisa Wang Biostatistician Princess Margaret Hospital Toronto, Ca

Hello there, I would like to test the agreement amongst 6 raters for nominal data on a scale from 1-4, and conduct a latent class analysis in R. How should the data be formatted and what code should I use? Thank you very much Lisa Wang Princess Margaret Hospital Biostatistics tel:416 946 4501

Hello there, I would like to plot a graph with the x axis's label displayed at a 45 angle to the x axis instead of horizontal to it as the label is very long. What should I do? Thank you for your help in advance Lisa Wang Princess Margaret Hospital Toronto, Ca

Hi there, Could anybody help me on how to sort a dataframe by one variable in the dataframe? Thank you Lisa Wang Princess Margaret Hospital Toronto, Ca tel: 416 946 4501

...Frank E. Harrell, Jr,PhD; Robert M. Califf, MD; David B. Pryor, MD;Kerry L.Lee, PhD; Robert A. Rosait,MD.) Hope to hear from you and thanks Lisa Wang, MSc Project Organiser & Researcher Cancer Informatics, Ontario Cancer Institute/Princess Margaret Hospital, University Health Network; Email: lisawang at uhnres.utoronto.ca Phone: 416 946 4501 ext. 5201 Fax: 416 946 4619

Hello there, In gdata package, read.xls is to be used for reading excel data (from windows). The following is my code:('C:/session/sampledata.xls' is where the file is stored) data1<-read.xls('C:/session/sampledata.xls',sheet=1) and I got the following error message: Error in system(cmd, intern = !verbose) : perl not found Could you please tell me what I have done wrong and

Hello, Could you please let me know how to see the "mean" function in R . The following is what I see when type in "mean" and "enter" mean function (x, ...) UseMethod("mean") <environment: namespace:base> I would like to see how the function is writen. Thanks a lot Lisa Wang Toronto, Ca -------------- next part -------------- This e-mail may

Hello there, I would like to simulate X --Normal (20, 5) Y-- Normal (40, 10) and the correlation between X and Y is 0.6. How do I do it in R? Thank you very much Lisa Wang Msc. Princess Margaret Hospital Toronto, Ca

Hello, My name is Lisa and I'm a statistician at Princess Margare Hospital. I wonder if there is any function in R that calculate the Normal rankits based on Blom's approximation? Thank you very much Lisa Wang Msc. Princess Margaret hospital Toronto, Ca

Hello, I wonder when I do coxph in R: coxph( Surv(start, stop, event) ~ x, data=test) If x is a categorical varible (1,2,3,4,5), should I creat four dummy varibles for it? if yes, how can I get the overall p value on x other than for each dummy variable? Thanks Lisa Wang Princess Margaret Hospital Phone 416 946 4501

Hello there, I am doing analysis on survival data. How do I pick out a probability of survival at a chosen landmark time(for example, 3 years, 4 years) from the result of "survfit"? or any other functions? As I know, the result of 'survfit' only have the probabilities for all event or cencor time. Thank you very much Lisa Wang Princess Margaret Hospital Toronto, Ca tel:

Hello there, I tried so many times to download windows binary zip package but it told me that I don't have the access to do so. It worked for me a few months ago. Please help me with it. Thank you Lisa Wang Msc. Princess Margaret Hospital Toronto , Canada tel: (416) 946 4501 ext.5201

Hello there: Dear Dr. Murdoch, I'm a statistician at Princess Margaret Hospital. Could you please help me with the bootstrapping? Can boot function (along with boot.ci) handle multivariate statistics? My intention is that I want to group the outcome data and evaluate the proportion of patients who are positive for a marker within each group. (i.e. I have two variables, a predictor and

Hello there, I would like to produce a plot of x<-c(4,5,6),which is the mean of each group and y<-c('groupA','groupB','groupC'). plot (x,y) can not produce any graphics because y is not numerical. What should I do to produce this graphic? Thank you in advance Lisa Wang Princess Margaret Hospital Toronto,Ca

Hello there, In the e1071 package,'lca' function only works for binary data for Latent class analysis. Am I right? I would like to test the agreement amongst 6 raters for nominal data ona scale from 1-4, and conduct a latent class analysis. What package and what function may I use? Thank you very much Lisa Wang Princess Margaret Hospital tel: 416 946 4501

Hi there, I have a predictor varible "class" which is a categorical variable and a ' coxph' is used to find the coeffients. How can I plot the predicted survival proportion based on this model? Thanks Lisa Wang Princess Margaret Hospital Toronto tel 416 946 4501