Definition ❑ Hypothesis is a prediction regarding the possible outcome of a study, ❑ a predictive statement of the relation between two or more variables or a formal statement that presents the expected relationship between independent and dependent variables. ❑ Hypothesis is a statement or explanation that is suggested by knowledge or observation but has not, yet, been proved or disproved
❑ The purpose of a hypothesis is to find the answer to a question. A formalized hypothesis will force us to think about what results we should look for in an experiment. ❑ For a hypothesis to be termed a scientific hypothesis, it has to be something that can be supported or refuted through carefully crafted experimentation or observation.
N.B ❖ Hypotheses are always in declarative sentence form. ❖ A researcher can conduct a valid investigation without constructing a hypothesis. However, it is always good to construct a hypothesis as it will help to narrow down your focus of research. ❖ Not all studies have hypotheses as sometimes a study is designed to be exploratory
Characteristics of Hypothesis 1. It must be capable of verification (Testable): There must be methods and techniques used for data collection and analysis. However, new techniques may be developed to verify hypotheses during the research process. 2. It must be related to the existing body of knowledge: Be ensure that it emerges from an existing body of knowledge and adds to it. This could be achieved if the hypothesis has its foundation in existing knowledge. 3. It needs to be Precise, Simple and Specific: To be able to develop a good hypothesis, you need to equip yourself well in the literature review of your subject area.
Types of Hypotheses 1. Null Hypothesis (Statistical Hypothesis ) This is the conventional approach to making a prediction. It involves a statement that says there is no relationship between two groups that the researcher compares on a certain variable. The hypothesis also may state that there is no significant difference when different groups are compared with respect to a particular variable. In many cases, the purpose of a null hypothesis is to allow the experimental results to contradict the hypothesis and prove the point that there is a definite relationship. Null hypothesis is denoted by H O or H N and pronounced as “H oh” or “H-null”. Its phrasing indicates that the researchers anticipate that ‘no difference’ or ‘no relationship’ between groups or tested variables will be demonstrated by their study’s results. - Example: The neurodevelopmental treatment has no effect on hand functions of children with hemiplegia.
2. Alternative Hypothesis (Research Hypothesis) Research hypothesis involves a statement that says there is a relationship between two groups that the researcher compares on a certain variable. It is denoted by H A . Its phrasing indicates that the researchers predict that ‘a difference’ or ‘a relationship’ between groups or tested variables will be demonstrated by their study’s results. It may be directional or non-directional hypothesis.
a. Directional Hypothesis : This type of hypothesis suggests the outcome the investigator expects at the end of the study. Scientific journal articles generally use this form of hypothesis. The investigator bases this hypothesis on the trends apparent from previous research on this topic. If the hypothesis uses so-called comparison terms, such as greater,” “less,” “better,” or “worse, it is directional because it predicts that there will be a difference between the two groups and it specifies how the two groups will differ. − Example: The neurodevelopmental treatment may improve hand functions of children with hemiplegia.
b. Non Directional Hypothesis Certain hypothesis statements convey a relationship between the variables that the researcher compares, but do not specify the exact nature of this relationship. If the hypothesis simply predicts that there will be a difference between the two groups, it is non-directional because it predicts that there will be a difference but does not specify how the groups will differ. This form of hypothesis is used in studies where there is no sufficient past research on which to base a prediction. Example: The neurodevelopmental treatment may affect hand functions of children with hemiplegia.
Components of Hypothesis variables population Relation
Sources of Hypothesis 1. Reading Material- Published books, Journals, Magazines, Seminar Reports 2. Principle of Theories – Rule of Law, Basic Structure etc., 3. Personal Experience .
Process of Hypothesis Testing • Stating the hypothesis (Null or Alternative). • Setting the criteria for a decision. • Collecting data. • Evaluate the Null hypothesis.
Possible Outcomes in Hypothesis Testing (Decision) 1. Accepting a true null hypothesis (Correct Decision) 2. Rejecting a false null hypothesis (Correct Decision) 3. Rejecting a true null hypothesis (Type I Error): The null hypothesis (H 0 ) is wrongly rejected. 4. Accepting a false null hypothesis (Type II Error): The null hypothesis H 0 , is not rejected when it is in fact false.
Examples: A type I error would occur if we concluded that the two interventions produced different effects when in fact there was no difference between them. A type II error would occur if it were concluded that the two interventions produced the same effect, that is, there is no difference between the two interventions on average, when in fact they produced different ones.