External Email - Use Caution Hi Dr. Greve, Sorry to bring this back up, but I didn't fully understand how to calculate the variance in order to get the confidence intervals for each covariate, so I wanted to double check the steps. A colleague in the lab is helping me to derive the variance using Matlab, and just wanted to make sure of the formula I would use:
variance of B = rvar.mgh * inverse(transpose(Xg.dat)*(Xg.dat)) Is this the correct formula to derive variance in Matlab? Thanks again for your help, Batool On Fri, Oct 9, 2020 at 5:46 AM Douglas N. Greve <dgr...@mgh.harvard.edu> wrote: > You can standardize them yourself. rvar.mgh is the residual variance and > Xg is the design matrix. Between those and the beta values, you can > standarize the betas > > On 10/7/2020 3:39 PM, Batool Rizvi wrote: > > External Email - Use Caution > Hi Dr. Greve, > > Thank you for your response! Not sure if you already addressed this, but > my second question was whether there is a way to derive the (95%) > confidence intervals for my covariates that were included in the mri_glmfit > analyses? > > Thanks again! > Batool > > On Wed, Oct 7, 2020 at 7:31 AM Douglas N. Greve <dgr...@mgh.harvard.edu> > wrote: > >> >> >> On 10/6/2020 4:26 PM, Batool Rizvi wrote: >> >> External Email - Use Caution >> Hi, >> >> I had a couple additional questions related to this topic. >> >> 1. The beta-coefficients I derived from using the mri_segstats command >> with the input beta.mgh, are these values unstandardized? >> >> Yes, that have not been standarized >> >> >> 2. Just wondering, is there a possible way to also derive 95% confidence >> intervals for my covariates that were included in the mri_glmfit analyses? >> >> You can standardize them yourself. rvar.mgh is the residual variance and >> Xg is the design matrix. Between those and the beta values, you can >> standarize the betas >> >> >> Thanks so much for your help! >> Batool >> >> >> The information in this e-mail is intended only for the person to whom it >> is addressed. If you believe this e-mail was sent to you in error and the >> e-mail contains patient information, please contact the Mass General >> Brigham Compliance HelpLine at >> http://secure-web.cisco.com/1oeuP1CzRGXyZACmbwMuqld1TrYcwL3TDl8MZpn966QR9gkU-Abn3WbJ1JEIIoN9ych7SmMaBn7tRCu3p4Cup0jsvS0gRdtRc17azV8J6gCwwz6TjdxbMT0Bg-VRkGtzbd-2-hJBChNMP2steBFwfWPqnCcu4BnEIU7ykAg-pHgFgtFYGNZua_cNI3G1FpSuED0ZdQqBdJf5DVSwyTlOorIm_Hy6sjCib65562S0sKBWUWN1UGaZYBCQdHY9rIb8KFqXkRS10WrM--C4bRhQN5A/http%3A%2F%2Fwww.massgeneralbrigham.org%2Fcomplianceline >> . If the e-mail was >> sent to you in error but does not contain patient information, please >> contact the sender and properly dispose of the e-mail. >> > > The information in this e-mail is intended only for the person to whom it > is addressed. If you believe this e-mail was sent to you in error and the > e-mail contains patient information, please contact the Mass General > Brigham Compliance HelpLine at > http://secure-web.cisco.com/1oeuP1CzRGXyZACmbwMuqld1TrYcwL3TDl8MZpn966QR9gkU-Abn3WbJ1JEIIoN9ych7SmMaBn7tRCu3p4Cup0jsvS0gRdtRc17azV8J6gCwwz6TjdxbMT0Bg-VRkGtzbd-2-hJBChNMP2steBFwfWPqnCcu4BnEIU7ykAg-pHgFgtFYGNZua_cNI3G1FpSuED0ZdQqBdJf5DVSwyTlOorIm_Hy6sjCib65562S0sKBWUWN1UGaZYBCQdHY9rIb8KFqXkRS10WrM--C4bRhQN5A/http%3A%2F%2Fwww.massgeneralbrigham.org%2Fcomplianceline > . If the e-mail was sent > to you in error but does not contain patient information, please contact > the sender and properly dispose of the e-mail. >
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