Hypothesis

Hypothesis n Hypothesis : Is a formal statement of the expected relationships between two or more variables in a specified population? The hypothesis translates the research problem and purpose into a clear explanation or prediction of expected results or outcomes of the study. n A clearly stated hypothesis includes the variables to be manipulated or measured, identifies the population to be examined, and indicates the proposed outcomes for the study. n Hypothesis also influences the study design, sampling technique, data collection and analysis methods, and interpretation of findings. n Converts the question into a statement that predicts an expected outcome Types of hypothesis: ** Simple or complex: o A Simple hypothesis: concerns the relationship between one independent and one dependent variable (vicariate study). In experimental studies the independent variable may be considered the cause, and the dependent variable may be considered as the effect. · Example: there is a negative relationship between denial and reports of anxiety among post myocardial infarction patients. o A complex hypothesis: Concerns a relationship where two or more independent variables, two or more dependent variables, or both, are examined in the same study (multivariate). · Example: there is a positive relationship between patient perception of pain control and (a) complaints of pain and (b) requests for pain medication. **.Null and research hypothesis o Null hypothesis (Ho) = Statistical hypothesis; predict that no relationship exists between variables. Usually a statement of no differences or no associations – an equality Sentence · There will be no difference in at-home and pre-school program children on pre-social and pre-literacy tests. Research hypothesis (H1) = Alternative hypothesis; state the expected relationship between variables. ** Non-directional and directional research hypothesis o Non directional hypothesis: the direction of the relationship is not presented. o Directional: the direction of the relationship is present. It should contain a predictive terms such as more than, greater than, decrease in, or positive correlation. It is the preferred type for nursing research studies. E.g. Anxiety levels are lower for preoperative hysterectomy patients who have practiced relaxation exercises than for preoperative hysterectomy patients who have not practiced relaxation exercises. Hypothesis Criteria o Is written in declarative sentences. o Is written in the present tense. There is a positive relationship between the number of times children have been hospitalized and their fear of hospitalization. o Contains the population. o Contains the variables. o Is empirically testable Purposes of hypothesis: o Allow theoretical propositions to be tested in the real world. o Guide the research design. o Dictate the type of statistical analysis for the data o Provide the reader with an understanding of the researchers expectations about the study before data collecting begins. The sources of hypothesis o From the researchers own experiences. o From previous research studies. o From theoretical propositions. This is the most important source of a hypothesis. This process of a hypothesis derivation involves deductive reasoning. A propositional statement is isolated from the study frame work and empirically tested. * Note (1): Nursing research involves both inductive and deductive means of formulating hypothesis. * Note (2): Hypothesis should always be written before the study and should not be changed after the study results are examined. Characteristics of hypotheses n Testability n Based on sound scientific theory/rationale n Hypotheses may not always be explicitly stated n Wording must include: n The variables n The population being studied n The predicted outcome of the hypothesis Directional vs. Non-Directional Hypotheses n Directional hypothesis ¨ Specifies the direction of the relationship between independent and dependent variables n Non-directional hypothesis ¨ Shows the existence of a relationship between variables but no direction is specified Examples n Directional hypothesis ¨ Cardiac patients who receive support from former patients have less anxiety and higher self-efficacy than other patients n Non-directional hypothesis ¨ There is a difference in anxiety and self-efficacy between cardiac patients who receive support from former patients and those who do not Research vs. Statistical Hypotheses n Research hypothesis = scientific hypothesis ¨ Statement about the expected relationship of the variables ¨ Can be directional or no directional n Statistical hypothesis = null hypothesis ¨ States there is no relationship between the variables Example: Statistical Hypothesis n Oxygen inhalation by nasal canola of up to 6L/min does not affect oral temperature measurement taken with an electronic thermometer. ¨ Variables? ¨ Other examples? What Makes a Good Hypothesis A good hypothesis: n is stated in declarative form and not as a question. n posits an expected relationship between variables. n reflects the theory or literature on which it is based. n should be brief and to the point. n is testable, which means that it can carry out the intent of the question reflected by the hypothesis.