双尾检验（Two-tailed Test）和单项检验（One-tailed Test）是统计学中常用的两种假设检验方法，在拒绝或接受原假设的方式上有所不同。双尾检验：在双尾检验中，我们关心的是样本统计量与原假设预期值之间是否存在显著差异，而不涉及方向性的假设。我们将研究兴趣放在样本统计量过大或者过小的情况下。所...
A two tailed test will have half of this (2.5%) in each tail. Very simply, the hypothesis test might go like this: A null hypothesis might state that the mean = x. You’re testing if the mean is way above this or way below. You run a t-test, which churns out a t-statisti...
In the examples below, I use an alpha of 5%. Each distribution has one shaded region of 5%. When you perform a one-tailed test, you must determine whether the critical region is in the left tail or the right tail. The test can detect an effect only in the direction that has the cri...
What is a one-tailed or two-tailed test?One-Tailed and Two-Tailed Test:In statistics, we can encounter many types of tests. On the other hand, we also have these two called the one-tailed and two-tailed tests. Each of these tests has its distinct characteristics and are both useful ...
When we consider the head as highly significant, the other one, which is the tail, would be considered not. That is a one-tailed test. On the other hand, if we consider both the tail and the head as a significant factor to the test, then it is a two-tailed test. To understand ...
A one-tailed test is also called a one-sided test, and a two-tailed test is also called a two-sided test. This standard table has been called, “Standard Normal Distribution Areas” (38), “Areas in Tail of the Standard Normal Distribution” (39), and “Areas Under the Standard ...
If you were doing a two-tailed test of the generic against the brand name product, you would have insight into whether the effectiveness of the product was equivalent or worse than the brand name product. In this instance, you can make a more educated decision. If the generic product is ...
The two-tail p-value is twice the one-tail p-value. If the actual difference (effect) went opposite to the predicted direction: The one-tail p-value equals one minus half the two-tailed value. So if the two-tailed p-value is 0.1, the one-tailed p-value is 0.95 ...
one-tailed test References in periodicals archive ? Comparing the means of the two subsets, the calculated t-statistic of 1.49 is statistically significant at the 10% level in a one-tail test (15.6% in a two-tail test). Patent infringement and royalty rates: is litigation a 'deterrent'?
In the literal sense, it is a one-tailed probability since, as you can see in Figure 1, the probability is the area in the right-hand tail of the distribution. However, the F ratio is sensitive to any pattern of differences among means. It is, therefore, a test of a two-tailed ...