# roc

1. ### Correlation and ROC analysis with repeated measures data

Hi all, I have a hypothetical study where participants are taking drug X per standard of care. I have 3 different timepoints (baseline, therapy, post-therapy follow-ups) at which participants have biomarker sampling and echocardiograms performed. Exploratory objective: efficacy; Exploratory...
2. ### What are the factors that best differentiate the two groups?

Hello Everyone, I am conducting a sports study. I have these data and I would like to answer this question: What are the factors that best differentiate the two groups? I have 2 groups of 17 professional athletes, 17 NBA and 17 MLB players with a total of 64 factors (kinetics and kinematics)...
3. ### obtaining the AUROC in a test (subset) with time-dependent (survival) ROC from Cox model

I have survival times and fixed baseline values of biomarkers and risk factors ( I actually have them measured longitudinally but want to deal with the baseline values first). I'd like to (ideally using SAS/PHREG) estimate my Cox PH model with the baseline variables in a (2/3 of data) training...
4. ### Comparing groups of data sets with the order of data points being taken into account

Hi everybody, I have a problem related to statistics, and I hope that you can help me out. First, an attempt at a short version of my problem: I have 2 data sets that consist of 3 sub-sets each that I want to compare with a methodology that takes the order of the data points into account. Now...
5. ### Statistical significance

Hi, I have the following problem and I would need some piece of advice to solve it: I have a group of 28 patients (17 survived, 11 died) and I am trying to find out if some of quantities are capable of discriminating survivors from non-survivors with a ROC analysis. For all the considered...

I want to add Area Under the Curve (AUC) from multiple meta analyses. AUC for each Meta analysis is given. How can I add them together?
7. ### Trouble in interpreting the C.I for AUC using SPSS

I calculated AUC using SPSS and the output was: 0.623, std.Error=0.056. p=0.055. lower Bound was 0.513 and upper was 0.743 How could it be that the p value is not significant and the lower Bound of C.I was more than 0.5? Am I missing something? Thanks
8. ### ROC analysis: different results using SPSS and MedCalc

Hi! I am analyzing a group of patients for which I have the values of a certain test variable X and their survival (1 or 0). I want to perform a ROC analysis and get the AUC value, and the optimal criterion by which I can divide the patients into surviving/non-surviving. The optimal criterion...
9. ### area under the ROC curve for a cutoff point

I kindly requested help about a study of mine concerning ROC curve analysis in medical diagnosis. I use R software programme to find optimal cutoff point for a continuous variable. Firstly, I generate a random continuous variable for a diseased and non-diseased subjects from normal...
10. ### ROC function from TTR Package

I was trying to verify how well the lag-returns are calculated from ROC function in TTR package. Following is the code that I am using: library(quantmod) library(TTR) startDate = "2001-01-01" endDate = "2013-12-01" getSymbols("VXX",src="yahoo",return.class='xts',from=startDate...
11. ### ROC curve and comparison of data from serial tests.

Hello! With the premise that I am a simple biotechnologist and I've never studied biostatistics at all, I have been assigned the task of analyzing some data I've obtained from two serial lab tests. With the first test I have no population issues, since the two groups I'm comparing are...
12. ### ROC curves and attitudes dilemma

Dear contributors, I am conducting a study looking at attitudes of a group to the use of music as a form of therapy for people with dementia. I want to see if they are positive, neutral or negative (at least negative or positive) in my sample (N=92). My hypothesis based on previous studies...
13. ### ROC Specify Cut - Offs

Hi, I am conducting a couple of ROC's to compare our sample with the results from other analyses and am a little stuck Basically other papers have looked at specific cut offs (e.g 50) however whenever I run the analysis in SPSS my cut offs are all varied, for example 50.5, or 48.5, which...
14. ### SPSS- How to do AUC/ROC analyses? Help

Dear all, Would be grateful for any help/pointers. I've spent the weekend trying to work out how to do area under the curve (ROC) analyses in spss 18. I've done it a couple of years ago but just can't recall how to input the data and where to find the requisite commands! I have the...