We can see that the term "one-tailed" refers to the tail of the distribution on the outcome variable. For instance, let's assume you are studying a new drug treatment for depression.
The drug has gone through some initial animal trials, but has not yet been tested on humans.
For example, our discussion about copying from winning proposals, the post reviewing the ERC grant, and the “ERC Lessons Learnt“.
Still, we highly advise researchers to seek assistance and consulting in order to solidify their hypothesis, and overall ERC grant application at large.
If your original prediction was not supported in the data, then you will accept the null hypothesis and reject the alternative.
The logic of hypothesis testing is based on these two basic principles: , and sometimes we just have to do things because they're traditions.
Again, notice that the term "two-tailed" refers to the tails of the distribution for your outcome variable.
The important thing to remember about stating hypotheses is that you formulate your prediction (directional or not), and then you formulate a second hypothesis that is mutually exclusive of the first and incorporates all possible alternative outcomes for that case.
There is no formal hypothesis, and perhaps the purpose of the study is to explore some area more thoroughly in order to develop some specific hypothesis or prediction that can be tested in future research. The way we would formally set up the hypothesis test is to formulate two hypothesis statements, one that describes your prediction and one that describes all the other possible outcomes with respect to the hypothesized relationship.
Your prediction is that variable A and variable B will be related (you don't care whether it's a positive or negative relationship).