The document discusses two-tailed and one-tailed tests. A two-tailed test is used when the alternative hypothesis is that a population parameter is not equal to some value, allowing it to be either greater than or less than. It tests for differences in either direction. A one-tailed test is used when interested in testing if the parameter is greater than or less than a value, but not both, and tests for differences in a single direction only. Key differences are that two-tailed tests are non-directional while one-tailed tests are directional, two-tailed tests reject in both tails and one-tailed in just one tail, and two-tailed tests determine if a relationship exists in either direction while one-

1. Subject Name: research methods in
management
Topic Name(s):Two tailed and One
tailed test
Lecture No:35
SAKSHI ARORA
ISBM
4/3/2023 Lecture Number, Unit Number 1

2. Two tailed and One tailed test
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3. Two tailed test
• If the null hypothesis that we are trying to reject is that a population parameter is
equal to some value, and the alternative hypothesis is that this population
parameter is not equal to this value, then the test is a two tailed test.
• In a two tailed test, we are willing to reject the null hypothesis if we find evidence
that the unknown parameter is either less than or greater than the hypothesized
value, and we do not specify ahead of time which it should be.
• If the question is whether or not the true unknown parameter is “different from”
or “not equal to” some specified value, then the test should be two-tailed.
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5. When use two tailed test
1. To test hypothesis or non-directional
hypothesis.
2. To find that there is any difference or not
between the means.
3. No concern about the direction or sign on
the difference.
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6. One tailed test
Sometimes we are only interested in testing to see if the true unknown parameter
is greater than some specified value, or less than some specified value, but not in
testing for both possibilities at once.
• In this case, the test will be either “left tailed” (if our alternative hypothesis is that
the parameter is less than the hypothesized value) or “right tailed” (greater than
the hypothesized value).
• Some people say that we shouldn’t make assumptions about whether the true
value is less than or greater than the hypothesized value, and that all tests should
be two tailed. I am sympathetic to this argument, but will consider both one and
two tailed tests.
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9. When use
1. To test alternative hypothesis and directional
hypothesis.
2. To concern about the direction or sign of the
difference is exists.
3. Wants to know which mean is large or small.
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10. • Content: One-tailed Test Vs Two-tailed Test
• Comparison Chart
• Definition
• Key Differences
• Conclusion
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11. BASIS OF COMPARISON ONE-TAILED TEST TWO-TAILED TEST
Meaning A statistical hypothesis test
in which alternative
hypothesis has only one
end, is known as one tailed
test.
A significance test in which
alternative hypothesis has
two ends, is called two-
tailed test.
Hypothesis Directional Non-directional
Region of rejection Either left or right Both left and right
Determines If there is a relationship
between variables in single
direction.
If there is a relationship
between variables in either
direction.
Result Greater or less than certain
value.
Greater or less than certain
range of values.
Sign in alternative
hypothesis
> or < ≠
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