diff --git a/src/ontology/stato.owl b/src/ontology/stato.owl
index 298ff78..404b364 100644
--- a/src/ontology/stato.owl
+++ b/src/ontology/stato.owl
@@ -914,6 +914,9 @@
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@@ -20528,6 +20596,59 @@ http://stat.ethz.ch/R-manual/R-patched/library/stats/html/binom.test.html#STATO_0000298
exact binomial test
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+ #Welch_t-test
+ http://purl.obolibrary.org/obo/IAO_0000122
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+
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+ #Welch_t-test
+ Welch t-test is a two sample t-test used when the variances of the 2 populations/samples are thought to be unequal (homoskedasticity hypothesis not verified). In this version of the two-sample t-test, the denominator used to form the t-statistics, does not rely on a 'pooled variance' estimate.
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+
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+ #Welch_t-test
+ Alejandra Gonzalez-Beltran
+
+
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+ #Welch_t-test
+ Orlaith Burke
+
+
+
+ #Welch_t-test
+ Philippe Rocca-Serra
+
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+ #Welch_t-test
+ Welsh t-test
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+ #Welch_t-test
+ Welch, B. L. (1947). "The generalization of "Student's" problem when several different population variances are involved". Biometrika 34 (1–2): 28–35. doi:10.1093/biomet/34.1-2.28
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+
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+ #Welch_t-test
+ adapted from wikipedia:
+http://en.wikipedia.org/wiki/Welch's_t_test
+
+last accessed: 2014-05-06
+
+
+
+ #Welch_t-test
+ t-test for independent means assuming unequal variance
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+
+
+ #Welch_t-test
+ t-test for independent means assuming unequal variance
+
#covariance
@@ -20603,6 +20724,11 @@ It uses a t-distribution for the test and assumes that the variables in the popu
#t-test-independent-means
Philippe Rocca-Serra
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+
+ #t-test-independent-means
+ two sample t-test
+
#t-test-independent-means
@@ -20616,12 +20742,12 @@ http://www.psychology.emory.edu/clinical/bliwise/Tutorials/TOM/meanstests/tind.h
#t-test-independent-means
- t-test for independent means
+ t-test for independent means assuming equal variance
#t-test-independent-means
- two sample t-test
+ t-test for independent means assuming equal variance