Contrast variable: Difference between revisions

Revision as of 02:57, 7 July 2011

Revision as of 15:16, 16 July 2011

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|title= A method for effectively comparing gene effects in multiple conditions in RNAi and expression-profiling research

|journal=Pharmacogenomics |volume=10 |issue= |pages=345-58

|year=2009 |month= |pmid= |doi=10.2217/PGS14622416.0910.13.345 |url=}}</ref>

. Associated with a contrast variable are two terms, standardized mean of

contrast variable ([[SMCV]]) and [[c+-probability]]. The SMCV is the ratio of mean to standard deviation of a contrast variable and the c+-probability is the probability that a contrast variable obtains a positive value. Traditional [[contrast]] is a statistical parameter defined only on the group [[mean]]s. A contrast variable allows us to consider not only group [[mean]]s but also group [[variance]]s in a comparison. In addition, the concept of contrast variable can help to derive the [[effect size]]s across any number of groups readily and smoothly

<ref name=ZhangJBiometBiostat2010>{{cite journal |author=Zhang XHD

|title= Contrast variable potentially providing a consistent interpretation to effect sizes

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|url= http://www.omicsonline.org/2155-6180/2155-6180-1-108.php}}</ref>

.

The concepts of contrast variable, [[SMCV]] and [[c+-probability]] were recently proposed for one-way [[ANOVA]] cases

<ref name=ZhangPharmacogenomics2009>{{cite journal |author=Zhang XHD

|title= A method for effectively comparing gene effects in multiple conditions in RNAi and expression-profiling research

|journal=Pharmacogenomics |volume=10 |issue= |pages=345-58

|year=2009 |month= |pmid= |doi=10.2217/PGS14622416.0910.13.345 |url=}}</ref>

and were then extended to multi-factor [[ANOVA]] cases

<ref name=ZhangPharmacogenomics2010>{{cite journal |author=Zhang XHD

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|title= Contrast variable potentially providing a consistent interpretation to effect sizes

|journal=Journal of Biometrics & Biostatistics |volume=1 |issue= |pages=108

|year=2010 |month= |pmid= |doi= doi:10.4172/2155-6180.1000108

|url= http://www.omicsonline.org/2155-6180/2155-6180-1-108.php}}</ref>

. When there are only two groups involved in a comparison, SMCV becomes [[SSMD]]. The contrast variable, [[SMCV]] and [[c+-probability]] are critical for deriving statistical methods for assessing the size of [[siRNA]] effects in genome-scale RNAi screens

<ref name=ZhangBook2011>{{cite book

|author= Zhang XHD

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* [[SSMD]]

* [[SMCV]]

* [[c+-probability]]

* [[Contrast (statistics)]]

* [[Dual-flashlight plot]]