search for: carcinogen

Dear R-listers, Does anybody know what is the correct source of "rats" dataset in survival package? The help gives the following information: Rat data from survival5 Description: 48 rats were injected with a carcinogen, and then randomized to either drug or placebo. The number of tumors ranges from 0 to 13; all rats were censored at 6 months after randomization. Usage: data(rats) Format: rat: id rx: treatment,(1=drug, 0=control) observation: within rat...

Hi, I would like to derive p-values for pair-wise comparison (Tukey's) of effects when the response is a count. I am trying a test case where y ~ Po( lambda(x) ). x has three levels : A, B and C with lambda(x) = 10, 20 and 20 respectively. Hence, p-values for the contrast C - B should distribute uniformally. I have implemented this test case as below but do not get uniform

...y in Environmental Health (Silent Spring Institute; Boston, MA) Silent Spring Institute is a non-profit scientific research group studying the environment and health. We are a multi-disciplinary team and international leader in research on everyday exposures to hormone disruptors, tests for breast carcinogens, and environmental links to breast cancer. We lead collaborative research teams that include top computer scientists, statisticians, and other scientists at Brown, Harvard, UC Berkeley, and elsewhere. We seek a research assistant or staff scientist with experience in computer science, data analys...

Hi all, I am looking for a clever way to create the following graph using R: I got information on the shares of some subgroups over time (summing up to 1 in each year). The graph I want to create should display the development of the individual shares over time by shading rectangulars for each share in a different color. Is there a clever of doing this? Thanks for your help Stefan

...alues are uniform only when the distribution is continuous. See > > Westfall, P.H. and Troendle, J.F. (2008). Multiple Testing with > Minimal Assumptions, Biometrical Journal 50, 745-755. > > Westfall, P.H., and Soper, K.A. (2001). "Using priors to improve > multiple animal carcinogenicity tests<http://pubs.amstat.org/doi/pdfplus/10.1198/016214501753208852 >> ", Journal of the American Statistical Association 96, 827-834. > > Westfall, P.H. and Wolfinger, R.D.(1997). "Multiple Tests with > Discrete Distributions<http://www.jstor.org/stable/2684683&...