Filtering is used to remove spots that are found to be inadequate by
performing the Wilcoxon signed rank-based gene expression
presence/absence detection algorithm.
This function performs the hypothesis test:
- H
: median(
) =
, corresponding to absence of
transcript.
- H
: median(
) >
, corresponding to presence of
transcript.
where
for each
in a
probe-pair in the probe-set represented by data.
Small
-values imply presence while large ones imply
absence of transcript. The detection call is computed by
thresholding the
-value as in:
- "P",if
-value <
.
- "M" if
<=
-value <
- "A" if
<=
-value
In SciCraft you have the option of filtering based on the following
three criterions
- Not removing the spots by selecting
``none'' in the Filtering parameter box.
- Remove all genes classified as absent by the rule above.
- Remove all genes classified as absent or marginal by the rule above.
Bjørn Kåre Alsberg
2006-04-06