I'd like to know whether an intensity signal in a microarray is large enough that, if its gene were downregulated, it would be detected. That is, what proportion of the probes can be "detected" in the target? I'm trying to explore this by dividing random subsets of the experimental (i.e. "R") intensities by a small factor, and asking what proportion of these simulated changes limma detects. Does this sound reasonable? Is there a better way? John Welsh Associate Professor Sidney Kimmel Cancer Center 10835 Altman Row San Diego, CA 92121 (858) 450-5990 ex.282 jwelsh@skcc.org

"John Welsh" <jwelsh@skcc.org> writes: > I'd like to know whether an intensity signal in a microarray is large > enough that, if its gene were downregulated, it would be > detected. That is, what proportion of the probes can be "detected" in > the target? I'm trying to explore this by dividing random subsets of > the experimental (i.e. "R") intensities by a small factor, and asking > what proportion of these simulated changes limma detects. Does this > sound reasonable? Is there a better way? Are you talking about a single chip or a multiple chip experiment? And the technology used is relevant as well (single-channel or dual-channel, and platform)? best, -tony -- Anthony Rossini Research Associate Professor rossini@u.washington.edu http://www.analytics.washington.edu/ Biomedical and Health Informatics University of Washington Biostatistics, SCHARP/HVTN Fred Hutchinson Cancer Research Center UW (Tu/Th/F): 206-616-7630 FAX=206-543-3461 | Voicemail is unreliable FHCRC (M/W): 206-667-7025 FAX=206-667-4812 | use Email CONFIDENTIALITY NOTICE: This e-mail message and any attachme...{{dropped}}