1.9 HYPOTHESES: 

A hypothesis is a conjectural statement of the relations between two or more variables (Kerlinger & Howard, 2000). It is a tentative answer to a research problem, expressed in the form of a clearly stated relation between the independent and the dependent variables (Nachmias & Nachmias, 1992). It is an assumption based on a series of facts for inferring the existence of relation or cause of existence of relation or cause of phenomena without actual proof yet.

1.9.1 Types of Hypothesis

There are two types of hypotheses: null hypothesis and alternative hypothesis. 

1.9.2 Null Hypothesis

The null hypothesis is sometimes referred to as a statistical hypothesis.  The null hypothesis is a statement which presumes that NO significant relationship or NO significant difference exists between the independent and dependent variables. For this hypothesis, any relationship between two variables or difference between groups is merely due to chance or error.

Example of a null hypothesis: There is no difference in performance of national examinations between form four students from rural secondary schools and form four students from urban secondary schools in Kenya.

1.9.3 Alternative Hypothesis:

The alternative hypothesis, also called research hypothesis, states that there is a relationship or difference between the stipulated variables but the researcher does not know the nature of such difference or relationship.  

Example of a research hypothesis: There is difference in the performance of national examinations between students from rural secondary schools and students from urban secondary schools. or There is a relationship between stress experienced on the job and job satisfaction of teachers."

1.9.4 Directional or Non-Directional Hypothesis

Another clarification of hypothesis can be directional or nondirectional. It states that a relationship or difference exists between the stipulated variables and goes further to specify the nature of the relationship or difference. This means that a relationship may be stated as being greater than, less than, increased, decreased, higher than, lower than etc.  Where the researcher is not sure of the form of the relationship he/she should not use a directional hypothesis especially where there is a high chance of obtaining an opposite relationship from the one hypothesized.

Example: The greater the stress experienced in the job, the lower the job satisfaction of the teachers.

1.9.5 Characteristic of Research Hypotheses

Research hypotheses share some common characteristics: 

• Hypotheses must be clear:  In order to test a hypothesis empirically, one has to define all the variables in the hypothesis.  Conceptual and operational definitions help clarify hypotheses.

• Hypotheses are specific:  The investigator has to point out the expected relations among the variables in terms of direction (positive or negative) and the conditions under which the relations will hold.  The hypothesis should also explicitly state the conditions under which the relations will be observed.

• Hypotheses should be testable:  This implies that variables stated in the hypotheses must be such that they are measurable and possibly quantifiable.  They should also be testable within a reasonable period of time.

• Good hypotheses must relate to the problem under investigation and must be based on a sound rationale derived from theory, previous research or professional experience: only reasonable intelligent and informed guess can qualify to be regarded as hypotheses.

• Scientific hypotheses are value  free: in principle, the researcher's own values, biases and subjective preferences have no place in the scientific approach.  

• The researcher must be aware of his personal biases and make them as explicit as possible.

• Variables stated in the hypotheses must be consistent with the purpose statement, objectives and the operationalized variables in the method section.

1.9.6 Sources of Research Hypotheses:

Researchers derive research problems and hypotheses either deductively from theories, inductively on the basis of direct observation, by using intuition, or by using a combination of these approaches, (Nachmias & Nachmias, 1996). Probably the best source for stimulating the statement of problems and hypotheses is the professional literature.

Literature review enables one either to generate worthwhile hypotheses or to modify and enrich the hypotheses he/she has already formulated as a result of experience or observation.  

A critical review of the professional literature familiarizes the researcher with the current state of knowledge, with concepts, theories, major variables, conceptual and operational definitions; with problems and hypotheses that others have studied; and with the research methods used.   Basing new research on the knowledge described in the professional literature contributes to the cumulative nature of scientific knowledge. Considering that thousands of articles and books in the social sciences are published every year, it is best to begin any search with one of the guides to published literature. These guides include reference books, bibliographies, indexes, abstracts, journals and statistical source books. Most universities libraries also offer online (computerized) database search service.