The choice of one-tailed or two-tailed tests follows the logic of the hypothesis that is being tested! The one-tailed test, if appropriate, will be more powerful.
no tail
· One-tailed test looks at the probability that the sample mean was either "greater than", or "less than or equal to" · Two-tailed test, sees if two means are different from each other (ie from different populations), or from the same population and tries to establish "equal to" or "not equal to
You could use a two-tailed t-test. You would use a two-tailed test instead of a one-tailed test because you are not hypothesizing which direction the difference will be. If you hypothesize before hand the direction of change, you could use a one-tailed test.
-2.58,2.58
A two-tailed test is both, upper and lower tailed!
The choice of one-tailed or two-tailed tests follows the logic of the hypothesis that is being tested! The one-tailed test, if appropriate, will be more powerful.
no tail
Alpha or significance level is usually 0.1 or 0.05 for a 2-tailed test.
· One-tailed test looks at the probability that the sample mean was either "greater than", or "less than or equal to" · Two-tailed test, sees if two means are different from each other (ie from different populations), or from the same population and tries to establish "equal to" or "not equal to
You could use a two-tailed t-test. You would use a two-tailed test instead of a one-tailed test because you are not hypothesizing which direction the difference will be. If you hypothesize before hand the direction of change, you could use a one-tailed test.
The answer depends on whether the test is one-tailed or two-tailed.One-tailed: z = 1.28 Two-tailed: z = 1.64
The answer depends on the distribution under consideration.
Two-tailed test Hi: µM-µF = 0 Because if it turns out that Hi: µM-µF ≠0, the difference may be greater or smaller
-2.58,2.58
91
A one tailed test allows you to test a one-sided hypothesis.