This statement is speculation, not a hypothesis. Aphid-infected plants that are exposed to ladybugs will have fewer aphids after a week than aphid-infected plants which are left untreated. Sandra says: "This hypothesis gives a clear indication of what is to be tested the ability of ladybugs to curb an aphid infestation , is a manageable size for a single experiment, mentions the independent variable ladybugs and the dependent variable number of aphids , and predicts the effect exposure to ladybugs reduces the number of aphids.
Ladybugs are a good natural pesticide for treating aphid infected plants. Sandra says: "This statement is not 'bite size. There is no clear indication of what will be measured to evaluate the prediction.
Throughout history, scientists have posed hypotheses and then set out to prove or disprove them. Staff Scientist Dave reminds that scientific experiments become a dialogue between and among scientists and that hypotheses are rarely if ever "eternal. A look at the work of Sir Isaac Newton and Albert Einstein, more than years apart, shows good hypothesis-writing in action. As Dave explains, "A hypothesis is a possible explanation for something that is observed in nature.
For example, it is a common observation that objects that are thrown into the air fall toward the earth. Sir Isaac Newton put forth a hypothesis to explain this observation, which might be stated as 'objects with mass attract each other through a gravitational field.
Newton's hypothesis demonstrates the techniques for writing a good hypothesis: It is testable. It is simple. It is universal. It allows for predictions that will occur in new circumstances. It builds upon previously accumulated knowledge e.
Like Newton's hypothesis, the one offered by Einstein has all of the characteristics of a good hypothesis. That's good news for scientists of all ages. There are always questions to answer and educated guesses to make! They are influenced by the change in independent variable. Example 1 The greater number of coal plants in a region independent variable increases water pollution dependent variable. If you change the independent variable building more coal factories , it will change the dependent variable amount of water pollution.
Example 2 What is the effect of diet or regular soda independent variable on blood sugar levels dependent variable? If you change the independent variable the type of soda you consume , it will change the dependent variable blood sugar levels.
You should not ignore the importance of the above steps. The validity of your experiment and its results rely on a robust testable hypothesis. Developing a strong testable hypothesis has few advantages, it compels us to think intensely and specifically about the outcomes of a study. Consequently, it enables us to understand the implication of the question and the different variables involved in the study.
Furthermore, it helps us to make precise predictions based on prior research. Hence, forming a hypothesis would be of great value to the research. Here are some good examples of testable hypotheses. More importantly, you need to build a robust testable research hypothesis for your scientific experiments. A testable hypothesis is a hypothesis that can be proved or disproved as a result of experimentation. To devise and perform an experiment using scientific method, you need to make sure that your hypothesis is testable.
To be considered testable, some essential criteria must be met:. Without these criteria, the hypothesis and the results will be vague. As a result, the experiment will not prove or disprove anything significant. What are your experiences with building hypotheses for scientific experiments? He now had a theory that organized previous results in a meaningful way—but he still needed to test it.
He hypothesized that if his theory was correct, he should observe that the presence of others improves performance in a simple laboratory task but inhibits performance in a difficult version of the very same laboratory task.
The cockroaches ran either down a straight runway an easy task for a cockroach or through a cross-shaped maze a difficult task for a cockroach to escape into a dark chamber when a light was shined on them. Thus he confirmed his hypothesis and provided support for his drive theory. When you write your research report or plan your presentation, be aware that there are two basic ways that researchers usually include theory.
The first is to raise a research question, answer that question by conducting a new study, and then offer one or more theories usually more to explain or interpret the results. This format works well for applied research questions and for research questions that existing theories do not address. The second way is to describe one or more existing theories, derive a hypothesis from one of those theories, test the hypothesis in a new study, and finally reevaluate the theory.
This format works well when there is an existing theory that addresses the research question—especially if the resulting hypothesis is surprising or conflicts with a hypothesis derived from a different theory. To use theories in your research will not only give you guidance in coming up with experiment ideas and possible projects, but it lends legitimacy to your work. Psychologists have been interested in a variety of human behaviors and have developed many theories along the way.
Using established theories will help you break new ground as a researcher, not limit you from developing your own ideas. There are three general characteristics of a good hypothesis. First, a good hypothesis must be testable and falsifiable.
Second, a good hypothesis must be logical. As described above, hypotheses are more than just a random guess. Hypotheses should be informed by previous theories or observations and logical reasoning. Typically, we begin with a broad and general theory and use deductive reasoning to generate a more specific hypothesis to test based on that theory. Occasionally, however, when there is no theory to inform our hypothesis, we use inductive reasoning which involves using specific observations or research findings to form a more general hypothesis.
Finally, the hypothesis should be positive. That is, the hypothesis should make a positive statement about the existence of a relationship or effect, rather than a statement that a relationship or effect does not exist. The nature of science is to assume that something does not exist and then seek to find evidence to prove this wrong, to show that really it does exist. That may seem backward to you but that is the nature of the scientific method.
The underlying reason for this is beyond the scope of this chapter but it has to do with statistical theory. Chiang, Dana C. Skip to content 2. Discover how theories are used to generate hypotheses and how the results of studies can be used to further inform theories.
Understand the characteristics of a good hypothesis. Key Takeaways A theory is broad in nature and explains larger bodies of data.
A hypothesis is more specific and makes a prediction about the outcome of a particular study. Like other scientists, psychologists use the hypothetico-deductive method.
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