Thread View: bionet.molbio.genearrays
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Started by Andrew McArthur
Mon, 18 Jun 2007 14:05
standard error of fold change when using a Universal Reference
Author: Andrew McArthur
Date: Mon, 18 Jun 2007 14:05
Date: Mon, 18 Jun 2007 14:05
126 lines
8353 bytes
8353 bytes
--Apple-Mail-1--142615523 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Hello all, We have performed an experiment that included replicated microarray analyses. We have 4 replicate RNA samples from three treatments (A, B, C) plus a Universal Reference RNA sample (UR) made up of equal amounts of all A, B, and C samples. All experimental RNA samples (A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3, C4) were Cy3 labeled and individually co-hybridized with Cy5 labeled Universal Reference. When all was said and done we calculated the mean and standard error for fold change of A, B, and C versus the Universal Reference. Now we want to calculate "through" the Universal Reference to compare A versus B. To calculate the mean fold change of A versus B we have simply divided the mean fold change of A against the UR by the mean fold change of B against the UR. The question now is how to calculate the standard error of the fold change of A versus B. Does anyone have a good reference for calculating the standard error of a ratio variable when the ratio is made of two means with their own standard errors? Much thanks, Andrew McArthur ------ Andrew G. McArthur, Ph.D. Email: amcarthur@mac.com, Web: http://mcarthurlab.blogspot.com --Apple-Mail-1--142615523 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 <HTML><BODY style=3D"word-wrap: break-word; -khtml-nbsp-mode: space; = -khtml-line-break: after-white-space; ">Hello all,<DIV><BR = class=3D"khtml-block-placeholder"></DIV><DIV>We have performed an = experiment that included replicated microarray analyses.=A0 We have 4 = replicate RNA samples from three treatments (A, B, C) plus a Universal = Reference RNA sample (UR) made up of equal amounts of all A, B, and C = samples.</DIV><DIV><BR class=3D"khtml-block-placeholder"></DIV><DIV>All = experimental RNA samples (A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3, = C4) were Cy3 labeled and individually co-hybridized with Cy5 labeled = Universal Reference.=A0 When all was said and done we calculated the = mean and standard error for fold change of A, B, and C versus the = Universal Reference.=A0=A0</DIV><DIV><BR = class=3D"khtml-block-placeholder"></DIV><DIV>Now we want to calculate = "through" the Universal Reference to compare A versus B.=A0 To calculate = the mean fold change of A versus B we have simply divided the mean fold = change of A against the UR by the mean fold change of B against the UR.=A0= The question now is how to calculate the standard error of the fold = change of A versus B.=A0</DIV><DIV><BR = class=3D"khtml-block-placeholder"></DIV><DIV>Does anyone have a good = reference for calculating the standard error of a ratio variable when = the ratio is made of two means with their own standard = errors?</DIV><DIV><BR class=3D"khtml-block-placeholder"></DIV><DIV>Much = thanks,</DIV><DIV>Andrew McArthur<BR><DIV><SPAN class=3D"Apple-style-span"= style=3D"border-collapse: separate; border-spacing: 0px 0px; color: = rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: = normal; font-variant: normal; font-weight: normal; letter-spacing: = normal; line-height: normal; text-align: auto; = -khtml-text-decorations-in-effect: none; text-indent: 0px; = -apple-text-size-adjust: auto; text-transform: none; orphans: 2; = white-space: normal; widows: 2; word-spacing: 0px; "><SPAN = class=3D"Apple-style-span" style=3D"border-collapse: separate; = border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; = font-size: 12px; font-style: normal; font-variant: normal; font-weight: = normal; letter-spacing: normal; line-height: normal; text-align: auto; = -khtml-text-decorations-in-effect: none; text-indent: 0px; = -apple-text-size-adjust: auto; text-transform: none; orphans: 2; = white-space: normal; widows: 2; word-spacing: 0px; "><SPAN = class=3D"Apple-style-span" style=3D"border-collapse: separate; = border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; = font-size: 12px; font-style: normal; font-variant: normal; font-weight: = normal; letter-spacing: normal; line-height: normal; text-align: auto; = -khtml-text-decorations-in-effect: none; text-indent: 0px; = -apple-text-size-adjust: auto; text-transform: none; orphans: 2; = white-space: normal; widows: 2; word-spacing: 0px; "><SPAN = class=3D"Apple-style-span" style=3D"border-collapse: separate; = border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; = font-size: 12px; font-style: normal; font-variant: normal; font-weight: = normal; letter-spacing: normal; line-height: normal; text-align: auto; = -khtml-text-decorations-in-effect: none; text-indent: 0px; = -apple-text-size-adjust: auto; text-transform: none; orphans: 2; = white-space: normal; widows: 2; word-spacing: 0px; "><SPAN = class=3D"Apple-style-span" style=3D"border-collapse: separate; = border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; = font-size: 12px; font-style: normal; font-variant: normal; font-weight: = normal; letter-spacing: normal; line-height: normal; text-align: auto; = -khtml-text-decorations-in-effect: none; text-indent: 0px; = -apple-text-size-adjust: auto; text-transform: none; orphans: 2; = white-space: normal; widows: 2; word-spacing: 0px; "><SPAN = class=3D"Apple-style-span" style=3D"border-collapse: separate; = border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; = font-size: 12px; font-style: normal; font-variant: normal; font-weight: = normal; letter-spacing: normal; line-height: normal; text-align: auto; = -khtml-text-decorations-in-effect: none; text-indent: 0px; = -apple-text-size-adjust: auto; text-transform: none; orphans: 2; = white-space: normal; widows: 2; word-spacing: 0px; "><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; "><BR class=3D"khtml-block-placeholder"></DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">------</DIV><DIV style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Andrew G. = McArthur, Ph.D.</DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">Email: amcarthur@mac.com, Web: = <A = href=3D"http://mcarthurlab.blogspot.com">http://mcarthurlab.blogspot.com</= A></DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: = 0px; margin-left: 0px; "><BR class=3D"khtml-block-placeholder"></DIV><BR = class=3D"Apple-interchange-newline"></SPAN></SPAN></SPAN></SPAN></SPAN></S= PAN> </DIV><BR></DIV></BODY></HTML>= --Apple-Mail-1--142615523--
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