Statistics and Probability Dictionary
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Two-Tailed Test
A test of a
statistical
hypothesis
, where the
region of rejection
is on both sides of the
sampling distribution
, is called a two-tailed test.
For example, suppose the
null
hypothesis
states that the mean is equal to 10. The alternative
hypothesis would be that the mean is less than 10 or greater than 10. The
region of rejection would consist of a range of numbers located located on both
sides of sampling distribution; that is, the region of rejection would consist
partly of numbers that were less than 10 and partly of numbers that were
greater than 10.