This is a multi-part message in MIME format.
------=_NextPart_000_000B_01C31347.00FBE5E0
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
We have a couple questions about alphasim, thresholding, and clustering.
1) We plan on running alphasim on our original functional dataset (not =
the tlrc'd one) and the voxel size is 1.875 X 1.875 X 7 mm. What should =
we select as our connectivity radius; we suspected 1.88, but would like =
feedback on that.
2) We have three groups of subjects, and wish to do all pairwise =
comparisons. With Bonferroni correction, we get p=3D.0167 (.05/3) for =
each test. Is .0167 the value we enter as -pthr into alphasim? Is the =
-pthr for alphasim one- or two-tailed (.0167 versus .008)?=20
3) Is it correct that the slider bar in define function is two-tailed?
4) When clustering, do we enter the two-tailed t-value associated with =
p=3D.0167 into 3dmerge?=20
5) Is there a way to display the data where color/intensity reflects =
p-values in clustered data from a t-test in order to examine trends?
Is there a better way to correct for multiple comparisons in group data =
(e.g., creating ROIs in hopes of reducing the number of comparisons, and =
reducing cluster size necessary for significance at our criteria)? Using =
.0167 removes most of the clusters in group analyses that have quite a =
few subjects in each group.
Thanks for your time and assistance,
Brian and Alecia Schweinsburg
------=_NextPart_000_000B_01C31347.00FBE5E0
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 6.00.2800.1141" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>
<DIV><FONT face=3DArial size=3D2>We have a couple questions about =
alphasim,=20
thresholding, and clustering.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>1) We plan on running alphasim on our =
original=20
functional dataset (not the tlrc'd one) and the voxel size is 1.875 X =
1.875 X 7=20
mm. What should we select as our connectivity radius; we suspected 1.88, =
but=20
would like feedback on that.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>2) We have three groups of subjects, =
and wish to do=20
all pairwise comparisons. With Bonferroni correction, we get p=3D.0167 =
(.05/3) for=20
each test. Is .0167 the value we enter as -pthr into alphasim? Is the =
-pthr for=20
alphasim one- or two-tailed (.0167 versus .008)? </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>3) Is it correct that the slider bar in =
define=20
function is two-tailed?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>4) When clustering, do we enter the =
two-tailed=20
t-value associated with p=3D.0167 into 3dmerge? </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>5) Is there a way to display the data =
where=20
color/intensity reflects p-values in clustered data from a t-test in =
order to=20
examine trends?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Is there a better way to correct for =
multiple=20
comparisons in group data (e.g., creating ROIs in hopes of reducing the =
number=20
of comparisons, and reducing cluster size necessary for significance at =
our=20
criteria)? Using .0167 removes most of the clusters in group analyses =
that have=20
quite a few subjects in each group.</FONT></DIV>
<DIV>
<P class=3DMsoNormal style=3D"MARGIN: 0in 0in 0pt"><FONT face=3DArial=20
size=3D2></FONT> </P>
<P class=3DMsoNormal style=3D"MARGIN: 0in 0in 0pt"><FONT face=3DArial=20
size=3D2></FONT> </P>
<P class=3DMsoNormal style=3D"MARGIN: 0in 0in 0pt"><FONT face=3DArial =
size=3D2>Thanks=20
for your time and assistance,</FONT></P>
<P class=3DMsoNormal style=3D"MARGIN: 0in 0in 0pt"><FONT face=3DArial =
size=3D2>Brian and=20
Alecia Schweinsburg</FONT></P></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV></FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV></BODY>
------=_NextPart_000_000B_01C31347.00FBE5E0--
------------------------------------------
Posted to Phorum via PhorumMail
