1. Hypothesis
A statement of predicted relationship between the independent and dependent variables
Example: Cigarette smoking is related to lung cancer.

2. Hypothesis Allows theoretical propositions to be tested
Suggests an answer to the research question
Provides the reader with an understanding of the researcher’s expectations
Guides the research design
Dictates the type of statistical analysis to be used

3. Testing a Hypothesis Advances scientific knowledge
Supports or fails to support the tested theory

4. Sources or Rationale for Hypotheses
Theories
Personal experience
Previous research studies

5. Generating a Hypotheses
Inductive reasoning
Deductive reasoning

6. Research Hypotheses
Directional
Nondirectional

7. Types of Hypotheses
Simple
Complex
Research Hypothesis
Null Hypothesis

8. Simple Hypothesis
The relationship between one independent and one dependent variable
Example: Birth weight is lower among infants of alcoholic mothers than among infants of nonalcoholic mothers.

9. Complex Hypothesis
Two or more independent variables, two or more dependent variables, or both
Example: More postpartum depression and feelings of inadequacy are reported by women who give birth by cesarean section than those who deliver vaginally.

10. Interaction Effects
The action of two variables in conjunction with each other
Example: Daily weight loss is greater for adults who follow a reduced calorie diet and exercise daily than for those who do not follow a reduced calorie diet and do not exercise daily.

11. Null Hypothesis May read as “H0” Predicts no relationship
Is statistically analyzed

12. Research Hypothesis May read as “H1”
States expected relationship between variables
Can be directional or nondirectional

13. Directional Hypotheses
States the direction of the relationship
Makes a prediction between variables
Comes from conceptual/theoretical frameworks or previous research

14. Statistical Analyses Evaluates the Null Hypothesis
Significance level in nursing at or below .05

15. Non directional Research Hypotheses
Predicts a relationship between variables
Does not predict direction of relationship
Example: There is a relationship between serotonin levels and SIDS.

16. Directional Research Hypothesis
Predicts the direction of the relationship
Makes researchers’ expectation clear
Allows precise statistical testing
Example: People who smoke are more likely to develop lung cancer than those who do not.

17. Nondirectional Research Hypotheses
The study has no theory to base the prediction on
Previous research findings may be contradictory

18. A Hypothesis Should (criteria)
be written in a declarative sentence
be written in the present tense
specify the population to be studied
reflect the problem statement or the purpose statement
contain all the variables
be empirically testable

19. Hypothesis Format
A correlational statement
A comparative statement

20. Hypothesis Format Promotes statistical analysis of data
Uses predictive terms

21. Hypothesis Used to test propositions of a theory
Cannot be PROVED or DISPROVED

22. Hypothesis
If Null Hypothesis is rejected, the research hypothesis is supported.
Example: Null = There is no relationship between studying and test grades.

23. Hypothesis Research hypothesis supported, theory also supported
Research hypothesis not supported, theory also not supported
Example: Research Hypothesis = Those who study get higher test grades than those who do not.

24. Hypotheses
Needed when the relationship between variables is being studied

25. When aren’t Hypotheses Needed?
in qualitative studies
in single-variable descriptive studies
in methodological studies

26. Research Questions May be Used
in place of hypotheses in some studies
in addition to hypotheses related to other areas of interest concerning the study topic

27. Guidelines for Critiquing Hypotheses and Research Questions
Does the study contain a hypothesis or hypotheses?
Is each hypothesis clearly worded and concise?
Is the hypothesis written in a declarative sentence?
Is each hypothesis directly tied to the study problem?
If there is a clearly identified study framework, is each hypothesis derived from this framework?

28. Guidelines for Critiquing Hypotheses and Research Questions
Does each hypothesis contain the population and at least two variables?
Is each hypothesis stated as a directional research hypothesis? If not, is the rationale given for the type of hypothesis that is stated?
Is it apparent that each hypothesis can be empirically tested?

29. Guidelines for Critiquing Hypotheses and Research Questions
Does each hypothesis contain only one prediction?
If the study contains research questions, are the questions precise and specific?
Do the research questions further delineate the problem area of the study?