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There are seven different types of research hypotheses.
Hypothesis A statement of predicted relationship between the independent and dependent variables Example: Cigarette smoking is related to lung cancer. 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 Testing a Hypothesis Advances scientific knowledge Supports or fails to support the tested theory Sources or Rationale for Hypotheses Theories Personal experience Previous research studies Generating a Hypotheses Inductive reasoning Deductive reasoning Research Hypotheses Directional Nondirectional Types of Hypotheses Simple Complex Research Hypothesis Null Hypothesis 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. 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. 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. Null Hypothesis May read as “H0” Predicts no relationship Is statistically analyzed Research Hypothesis May read as “H1” States expected relationship between variables Can be directional or nondirectional Directional Hypotheses States the direction of the relationship Makes a prediction between variables Comes from conceptual/theoretical frameworks or previous research Statistical Analyses Evaluates the Null Hypothesis Significance level in nursing at or below .05 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. 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. Nondirectional Research Hypotheses The study has no theory to base the prediction on Previous research findings may be contradictory 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 Hypothesis Format A correlational statement A comparative statement Hypothesis Format Promotes statistical analysis of data Uses predictive terms Hypothesis Used to test propositions of a theory Cannot be PROVED or DISPROVED Hypothesis If Null Hypothesis is rejected, the research hypothesis is supported. Example: Null = There is no relationship between studying and test grades. 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. Hypotheses Needed when the relationship between variables is being studied When aren’t Hypotheses Needed? in qualitative studies in single-variable descriptive studies in methodological studies 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 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? 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? 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? How to Write a Strong Hypothesis | Steps & ExamplesA hypothesis is a statement that can be tested by scientific research. If you want to test a relationship between two or more variables, you need to write hypotheses before you start your experiment or data collection.
Example: HypothesisDaily apple consumption leads to fewer doctor’s visits. Table of contents
What is a hypothesis?A hypothesis states your predictions about what your research will find. It is a tentative answer to your research question that has not yet been tested. For some research projects, you might have to write several hypotheses that address different aspects of your research question. A hypothesis is not just a guess – it should be based on existing theories and knowledge. It also has to be testable, which means you can support or refute it through scientific research methods (such as experiments, observations and statistical analysis of data). Variables in hypothesesHypotheses propose a relationship between two or more variables. An independent variable is something the researcher changes or controls. A dependent variable is something the researcher observes and measures. Example: Hypothesis In this example, the independent variable is exposure to the sun– the assumed cause. The dependent variable is the level of happiness– the assumed effect. Developing a hypothesis (with example)Step 1. Ask a questionWriting a hypothesis begins with a research question that you want to answer. The question should be focused, specific, and researchable within the constraints of your project. Example: Research question Step 2. Do some preliminary researchYour initial answer to the question should be based on what is already known about the topic. Look for theories and previous studies to help you form educated assumptions about what your research will find. At this stage, you might construct a conceptual framework to identify which variables you will study and what you think the relationships are between them. Sometimes, you’ll have to operationalise more complex constructs. Step 3. Formulate your hypothesisNow you should have some idea of what you expect to find. Write your initial answer to the question in a clear, concise sentence. Attending more lectures leads to better exam results. 4. Refine your hypothesisYou need to make sure your hypothesis is specific and testable. There are various ways of phrasing a hypothesis, but all the terms you use should have clear definitions, and the hypothesis should contain:
5. Phrase your hypothesis in three waysTo identify the variables, you can write a simple prediction inif…then form. The first part of the sentence states the independent variable and the second part states the dependent variable. If a first-year student starts attending more lectures, then their exam scores will improve. In academic research, hypotheses are more commonly phrased in terms of correlations or effects, where you directly state the predicted relationship between variables. The number of lectures attended by first-year students has a positive effect on their exam scores. If you are comparing two groups, the hypothesis can state what difference you expect to find between them. First-year students who attended most lectures will have better exam scores than those who attended few lectures. 6. Write a null hypothesisIf your research involves statistical hypothesis testing, you will also have to write a null hypothesis. The null hypothesis is the default position that there is no association between the variables. The null hypothesis is written as H0, while the alternative hypothesis is H1 or Ha. H0: The number of lectures attended by first-year students has no effect on their final exam scores.
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Frequently asked questions about writing hypothesesWhat is a hypothesis?
A hypothesis states your predictions about what your research will find. It is a tentative answer to your research question that has not yet been tested. For some research projects, you might have to write several hypotheses that address different aspects of your research question. A hypothesis is not just a guess — it should be based on existing theories and knowledge. It also has to be testable, which means you can support or refute it through scientific research methods (such as experiments, observations and statistical analysis of data). What are null and alternative hypotheses?
Null and alternative hypotheses are used in statistical hypothesis testing. The null hypothesis of a test always predicts no effect or no relationship between variables, while the alternative hypothesis states your research prediction of an effect or relationship. What is hypothesis testing?
Hypothesis testing is a formal procedure for investigating our ideas about the world using statistics. It is used by scientists to test specific predictions, called hypotheses, by calculating how likely it is that a pattern or relationship between variables could have arisen by chance.
Is this article helpful?235 25 You have already voted. Thanks :-) Your vote is saved :-) Processing your vote...Shona McCombesShona has a bachelor's and two master's degrees, so she's an expert at writing a great thesis. She has also worked as an editor and teacher, working with students at all different levels to improve their academic writing. |