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Hypothesis_111757.ppt PowerPoint presentation
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- 2. Introduction • The purposeof hypothesis testing is to determine whether there is enough statistical evidence in favor of a certain belief about a parameter. • An hypothesis is a preliminary or tentative explanation or postulate by the researcher of what the researcher considers the outcome of an investigation will be. It is an informed/educated guess. • It indicates the expectations of the researcher regarding certain variables. It is the most specific way in which an answer to a problem can be stated. 2
- 3. What is hypothesis •A tentative statement about a population parameter that might be true or wrong 3
- 4. THE DIFFERENCE BETWEENAN HYPOTHESIS AND A PROBLEM • Both a hypothesis and a problem contribute to the body of knowledge which supports or refutes an existing theory. • A hypothesis differs from a problem. • A problem is formulated in the form of a question; it serves as the basis or origin from which an hypothesis is derived. • A hypothesis is a suggested solution to a problem. • A problem (question) cannot be directly tested, whereas an hypothesis can be tested and verified. 4
- 5. WHEN IS ANHYPOTHESIS FORMULATED • An hypothesis is formulated after the problem has been stated and the literature study has been concluded. • It is formulated when the researcher is totally aware of the theoretical and empirical background to the problem. 5
- 6. PURPOSE AND FUNCTIONOF AN HYPOTHESIS • It offers explanations for the relationships between those variables that can be empirically tested. • It furnishes proof that the researcher has sufficient background knowledge to enable him/her to make suggestions in order to extend existing knowledge. • It gives direction to an investigation. • It structures the next phase in the investigation and therefore furnishes continuity to the examination of the problem. 6
- 7. CHARACTERISTICS OF ANHYPOTHESIS • It should have elucidating power. • It should strive to furnish an acceptable explanation of the phenomenon. • It must be verifiable. • It must be formulated in simple, understandable terms. • It should corresponds with existing knowledge. 7
- 8. Types of Hypotheses 1.Descriptive Hypotheses: • These are propositions that describe the characteristics ( such as size, form or distribution) of a variable. The variable may be an object, person, organization etc. , e.g., The rate of unemployment among arts graduates is higher than that of commerce graduates. The educational system is not oriented to human resource needs of a country. 2. Relational Hypotheses. • These are propositions which describe the relationship between two variables. e. g. , Families with higher incomes spend more for recreation Upper – class people have fewer children than lower class people. 8
- 9. Cont… 3. Causal Hypotheses –It state that the existence of, or a change in, one variable Causes or leads to an effect on another variable. – The first variable is called the independent variable, and the latter the dependent variable. – When dealing with causal relationships between variables the researcher must consider the direction in which such relationship flow e.g: which is cause and which is effect 4. Working Hypotheses • While planning the study of a problem, hypotheses are formed. • Initially they may not be very specific. In such cases, they are referred to as ‘ working hypotheses’ which are subject to modification as the investigation proceeds. 9
- 10. Cont… 5. Null Hypotheses •This hypotheses are formulated for testing statistical significance, since, this form is a convenient approach to statistical analysis. As the test would nullify the null hypotheses. e.g., : There is a relationship between a family’s income and expenditure on recreation, a null hypothesis may state: There is no relationship between families income level and expenditure on recreation. 6. Statistical Hypotheses • These are statements about a statistical population. These are derived from a sample. These are quantitative in nature in that they are numerically measurable eg: Group A is older than B’ 10