 |
BUILT-IN MATHEMATICA SYMBOL
SiegelTukeyTest
SiegelTukeyTest[{data1, data2}]
tests whether the variances of 
and 
are equal.
SiegelTukeyTest[dspec, 
]
tests a dispersion measure against
.
SiegelTukeyTest[dspec, 
, "property"]
returns the value of 
.
Details and Options
- SiegelTukeyTest performs a hypothesis test on
and 
with null hypothesis 
that the ratio of the true population variances 
against 
. - By default a probability value or
-value is returned. - A small
-value suggests that it is unlikely that 
is true. - The argument
can be any positive real number. - The data in dspec must be univariate
. - SiegelTukeyTest assumes the data is symmetric about a common median.
- SiegelTukeyTest[data,
, "HypothesisTestData"] returns a HypothesisTestData object htd that can be used to extract additional test results and properties using the form htd["property"]. - SiegelTukeyTest[data,
, "property"] can be used to directly give the value of 
. - Properties related to the reporting of test results include:
-
"PValue" list of 
-values"PValueTable" formatted table of 
-values"ShortTestConclusion" a short description of the conclusion of a test "TestConclusion" a description of the conclusion of a test "TestData" list of pairs of test statistics and 
-values"TestDataTable" formatted table of 
-values and test statistics"TestStatistic" list of test statistics "TestStatisticTable" formatted table of test statistics - The test statistic is computed for the pooled sample
as 
where 
if 
is from 
and zero otherwise, and 
are ranks associated with each 
. The statistic is assumed to follow a NormalDistribution under 
. - SiegelTukeyTest is a less powerful ranks-based test than ConoverTest and is an alternative to the FisherRatioTest when the
is not normally distributed. - The following options can be used:
-
AlternativeHypothesis "Unequal" the inequality for the alternative hypothesis SignificanceLevel 0.05 cutoff for diagnostics and reporting VerifyTestAssumptions Automatic set which diagnostic tests to run - For the SiegelTukeyTest, a cutoff
is chosen such that 
is rejected only if 
. The value of 
used for the 
and 
properties is controlled by the SignificanceLevel option. This value 
is also used in diagnostic tests of assumptions including tests for symmetry. By default 
is set to 
. - Named settings for VerifyTestAssumptions in SiegelTukeyTest include:
-
"Symmetry" verify that all data is symmetric
Examplesopen all
Basic Examples (2)
Test variances from two populations for equality:
| In[1]:= |
| In[2]:= |
| Out[2]= |  |
Create a HypothesisTestData object for further property extraction:
| In[3]:= |
| Out[3]= |  |
| In[4]:= |
| Out[4]= |  |
Test the ratio of the variances of two populations against a particular value:
| In[1]:= |
| In[2]:= |
| Out[2]= |  |
| In[3]:= |
| Out[3]= |  |
Perform the test with alternative hypothesis 
:
| In[4]:= |
| Out[4]= |  |
New in 8
