The rationale for using a one-tailed test should be provided.

Because the direction of change is predicted all the tests are one-tailed.

The test statistic is the total number of heads (one-tailed).

The treatment has a beneficial effect" is the more informative result of a one-tailed test. "

Disagreements over one-tailed tests flow from the philosophy of science.

A one-tailed t-test was performed and the following results were obtained.

Each of these statistics can be used to carry out either a one-tailed or two-tailed test.

The greatest objection to one-tailed hypotheses is their potential subjectivity.

Fisher's original (Lady tasting tea) example was a one-tailed test.

Except that... there is a justification for one-tailed tests after all.

Poor statistical reporting practices have contributed to disagreements over one-tailed tests.

Note that this is a two-tailed test, rather than a one-tailed test.

One-tailed tests can suppress the publication of data that differs in sign from predictions.

If we were looking for significance at the 5% level, this result indicates that the die is loaded to give many 6's (one-tailed test).

If HA had specified the nature of the difference, this would have been a one-tailed hypothesis.

Note that to do this we cannot simply double the one-tailed p-value unless the probability of the event is 1/2.

All significant differences were confirmed by paired, one-tailed t-tests.

One-tailed tests of significance are used because the hypotheses are directional.

All statistical comparisons were made using one-tailed, unpaired Student's t-tests.

Some tests (for instance the χ goodness of fit test) are inherently one-tailed.

In some cases, the one-tailed test gave a statistically significant result when the appropriate two-tailed test does not.

Advice concerning the use of one-tailed hypotheses has been inconsistent and accepted practice varies among fields.

Each is tested with a one-tailed chi-square test.

A one-tailed hypothesis is said to have directionality.

I'll also deal with the related topics of one-tailed vs two-tailed tests, and hypothesis testing.