The “null hypothesis” is the hypothesis in research (and statistics) that claims there is no statistically significant relationship between the experimental (dependent) variables and the observed results or data collected.
There is an assumption that the null hypothesis is true, unless research findings indicate otherwise. Rejecting the null hypothesis can be the central task of research.
The null hypothesis can be denoted in statistics as .
The extent to which the results of a research experiment can be generalised to other contexts.
Contrast with internal validity.
The extent to which the results of a research experiment can be attributed to the independent variable under consideration, rather than to some confounding variable, through minimisation of systematic error (bias).
Contrast to external validity.
When researchers (or the public) assume a relationship exists between variables which occur together, when there is actually no correlation between the variables. The reasons for assuming a relationship between variables can be driven by personal biases, racism, “common sense” or other cognitive biases.