Research Methodology Hypothesis Hyposthesis A hypothesis (plural hypotheses) is a precise, testable statement of what the researcher(s) predict will be the outcome of the study. It is stated at the start of the study. This usually involves proposing a possible relationship between two variables: the independent variable (what the researcher changes) and the dependent variable (what the research measures). A hypothesis is a tentative statement about the relationship between two or more variables. It is a specific, testable prediction about what you expect to happen in a study. For example, a study designed to look at the relationship between sleep deprivation and test performance might have a hypothesis that states, "This study is designed to assess the hypothesis that sleep-deprived people will perform worse on a test than individuals who are not sleep-deprived." The Hypothesis in the Scientific Method In the scientific method, whether it involves research in psychology, biology, or some other area, a hypothesis represents what the researchers think will happen in an experiment.1 The scientific method involves the following steps: 1. Forming a question 2. Performing background research 3. Creating a hypothesis 4. Designing an experiment 5. Collecting data 6. Analyzing the results 7. Drawing conclusions 8. Communicating the results Formulating a Hypothesis • In many cases, researchers might draw a hypothesis from a specific theory or build on previous research. For example, prior research has shown that stress can impact the immune system. So a researcher might hypothesize: "People with high-stress levels will be more likely to contract a common cold after being exposed to the virus than people who have low-stress levels." • In other instances, researchers might look at commonly held beliefs or folk wisdom. "Birds of a feather flock together" is one example of folk wisdom that a psychologist might try to investigate. The researcher might pose a specific hypothesis that "People tend to select romantic partners who are similar to them in interests and educational level." Elements of a Good Hypothesis So how do you write a good hypothesis? When trying to come up with a hypothesis for your research or experiments, ask yourself the following questions: • • • Is your hypothesis based on your research on a topic? Can your hypothesis be tested? Does your hypothesis include independent and dependent variables? Falsifiability • In the scientific method, falsifiability is an important part of any valid hypothesis.1 In order to test a claim scientifically, it must be possible that the claim could be proven false. • Students sometimes confuse the idea of falsifiability with the idea that it means that something is false, which is not the case. What falsifiability means is that if something was false, then it is possible to demonstrate that it is false. Types of hypothesis 01 Alternate Hypothesis 02 Nondirectional Hypothesis 03 Null Hypothesis 04 Directional Hypothesis Alternate Hypothesis • • • The alternative hypothesis states that there is a relationship between the two variables being studied (one variable has an effect on the other). An experimental hypothesis predicts what change(s) will take place in the dependent variable when the independent variable is manipulated. It states that the results are not due to chance and that they are significant in terms of supporting the theory being investigated. Examples of an alternative hypothesis: • • "Children who receive a new reading intervention will perform better than students who did not receive the intervention.“ "Adults will perform better on a memory task than children." Null Hypothesis • • The null hypothesis states that there is no relationship between the two variables being studied (one variable does not affect the other). There will be no changes in the dependent variable due to the manipulation of the independent variable. It states results are due to chance and are not significant in terms of supporting the idea being investigated. Examples of a null hypothesis include: • • "Children who receive a new reading intervention will have scores different than students who do not receive the intervention.“ "There will be no difference in scores on a memory recall task between children and adults." Nondirectional Hypothesis • • A non-directional (two-tailed) hypothesis predicts that the independent variable will have an effect on the dependent variable, but the direction of the effect is not specified. It just states that there will be a difference. E.g., there will be a difference in how many numbers are correctly recalled by children and adults. Directional Hypothesis • • A directional (one-tailed) hypothesis predicts the nature of the effect of the independent variable on the dependent variable. It predicts in which direction the change will take place. (i.e. greater, smaller, less, more) E.g., adults will correctly recall more words than children. • Simple hypothesis: This type of hypothesis suggests that there is a relationship between one independent variable and one dependent variable. • Complex hypothesis: This type of hypothesis suggests a relationship between three or more variables, such as two independent variables and a dependent variable. • Statistical hypothesis: This hypothesis uses statistical analysis to evaluate a representative sample of the population and then generalizes the findings to the larger group. • Logical hypothesis: This hypothesis assumes a relationship between variables without collecting data or evidence.
