12 research outputs found
The Inuence of Misspecified Covariance on False Discovery Control when Using Posterior Probabilities
This paper focuses on the influence of a misspecified covariance structure on
false discovery rate for the large scale multiple testing problem.
Specifically, we evaluate the influence on the marginal distribution of local
fdr statistics, which are used in many multiple testing procedures and related
to Bayesian posterior probabilities. Explicit forms of the marginal
distributions under both correctly specified and incorrectly specified models
are derived. The Kullback-Leibler divergence is used to quantify the influence
caused by a misspecification. Several numerical examples are provided to
illustrate the influence. A real spatio-temporal data on soil humidity is
discussed.Comment: 22 pages, 5 figure
Power-enhanced multiple decision functions controlling family-wise error and false discovery rates
Improved procedures, in terms of smaller missed discovery rates (MDR), for
performing multiple hypotheses testing with weak and strong control of the
family-wise error rate (FWER) or the false discovery rate (FDR) are developed
and studied. The improvement over existing procedures such as the \v{S}id\'ak
procedure for FWER control and the Benjamini--Hochberg (BH) procedure for FDR
control is achieved by exploiting possible differences in the powers of the
individual tests. Results signal the need to take into account the powers of
the individual tests and to have multiple hypotheses decision functions which
are not limited to simply using the individual -values, as is the case, for
example, with the \v{S}id\'ak, Bonferroni, or BH procedures. They also enhance
understanding of the role of the powers of individual tests, or more precisely
the receiver operating characteristic (ROC) functions of decision processes, in
the search for better multiple hypotheses testing procedures. A
decision-theoretic framework is utilized, and through auxiliary randomizers the
procedures could be used with discrete or mixed-type data or with rank-based
nonparametric tests. This is in contrast to existing -value based procedures
whose theoretical validity is contingent on each of these -value statistics
being stochastically equal to or greater than a standard uniform variable under
the null hypothesis. Proposed procedures are relevant in the analysis of
high-dimensional "large , small " data sets arising in the natural,
physical, medical, economic and social sciences, whose generation and creation
is accelerated by advances in high-throughput technology, notably, but not
limited to, microarray technology.Comment: Published in at http://dx.doi.org/10.1214/10-AOS844 the Annals of
Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Classes of Multiple Decision Functions Strongly Controlling FWER and FDR
This paper provides two general classes of multiple decision functions where
each member of the first class strongly controls the family-wise error rate
(FWER), while each member of the second class strongly controls the false
discovery rate (FDR). These classes offer the possibility that an optimal
multiple decision function with respect to a pre-specified criterion, such as
the missed discovery rate (MDR), could be found within these classes. Such
multiple decision functions can be utilized in multiple testing, specifically,
but not limited to, the analysis of high-dimensional microarray data sets.Comment: 19 page
Quality control in resting-state fMRI: the benefits of visual inspection
Background: A variety of quality control (QC) approaches are employed in resting-state functional magnetic resonance imaging (rs-fMRI) to determine data quality and ultimately inclusion or exclusion of a fMRI data set in group analysis. Reliability of rs-fMRI data can be improved by censoring or “scrubbing” volumes affected by motion. While censoring preserves the integrity of participant-level data, including excessively censored data sets in group analyses may add noise. Quantitative motion-related metrics are frequently reported in the literature; however, qualitative visual inspection can sometimes catch errors or other issues that may be missed by quantitative metrics alone. In this paper, we describe our methods for performing QC of rs-fMRI data using software-generated quantitative and qualitative output and trained visual inspection.
Results: The data provided for this QC paper had relatively low motion-censoring, thus quantitative QC resulted in no exclusions. Qualitative checks of the data resulted in limited exclusions due to potential incidental findings and failed pre-processing scripts.
Conclusion: Visual inspection in addition to the review of quantitative QC metrics is an important component to ensure high quality and accuracy in rs-fMRI data analysis
Optimal Rejection Curves for Exact False Discovery Rate Control
Finner et al. (2012) provided multiple hypothesis testing procedures based on a nonlinear rejection curve for exact false discovery rate control. This paper constructs classes of such procedures and compares the most powerful procedure in each class to competing procedures