In HTAB there are three kinds of Hypothesis - Research Hypothesis, Statistical Hypothesis and Substantive Hypothesis. Research Hypothesis is a statement of what the researcher believes will be the outcome of an experiment or a study. Statistical Hypothesis is a more formal structure derived from the research hypothesis. Substantive Hypothesis is a statistically significant difference which does not imply a material substantive difference. (Business Statistics 4e by Ken Black).
A preconceived conclusion is an inevitable outcome of Research Hypothesis. The researcher tends to become biased. For example, older workers are more loyal to a company. That may true in most cases. But it is still a hypothesis. There maybe some old workers who resent company policy to the extent that they have been nursing grievances or have not been allowing new employees to prove their potential in the company.
Statistical hypothesis is to some extent also preconceived . Although it has a more formal structure it is essentially based on the preconceived notion of the Research Hypothesis. Substantive Hypothesis is the significant difference which does not always encompass material or quantitative difference.
There are two parts of Statistical hypothesis - a null hypothesis ...