What is a directional hypothesis? This is also known as a one-tailed hypothesis and involves researchers predicting the direction or effect one variable (the independent variable normally) will have on another (the dependent variable) be it positive or negative. For example in a test between boys and girls the researchers may predict that boys may perform better than girls. The direction they are predicting here is that boys will perform “better”.
What is a non-directional hypothesis? Also known as a two-tailed hypothesis where the researchers predict that the independent variable will affect the dependent variable but without stating the direction. An example of this is: “There will be a significant difference between boys and girls test scores”
The direction here is not stated but the hypothesis is predicting a difference to occur.
So what is a null-hypothesis then? This is where researchers believe there will be no significant difference evident in the findings. For example in a study between boys and girls to see who perform better, the null hypothesis would predict no significant difference between boys and girls. Any results observed are proposed to occur due to chance and a statistical test could be used to measure any results. If the test showed a significant difference then researchers would reject/refute the null hypothesis as evidently there would then be a significant difference observed.
To cite this article:
Saj Devshi – http://www.loopa.co.uk/what-is-a-hypothesis-in-aqa-psychology