Summary
A testable explanation for an observation that can be supported or refuted by evidence.
In depth
A hypothesis makes a prediction: if X, then Y. The null hypothesis states no effect. Evidence can support but never prove a hypothesis with certainty; it may refute it.
A good hypothesis is specific, testable and falsifiable. Multiple working hypotheses reduce bias. Predictions follow logically.
Key idea: experiments test predictions to support or refute hypotheses.
A hypothesis is a tentative, testable explanation for an observation, usually stated as a prediction linking cause and effect: if the independent variable changes, then the dependent variable will change in a specific way, because of a stated mechanism.
A good hypothesis is specific, falsifiable and based on existing knowledge. It is accompanied by a null hypothesis that states there is no effect. Evidence can support or fail to support a hypothesis but cannot prove it with certainty; repeated support builds confidence.
Example: if plants are given more nitrate, then they will grow taller because nitrogen is needed for proteins.
Common mistake: a hypothesis is not just a guess or a question, and it is not the same as a theory.
Frequently asked questions
What is Hypothesis?
A testable explanation for an observation that can be supported or refuted by evidence.
Which area of biology covers Hypothesis, and how advanced is it?
Hypothesis is one of the 51 topics in Lab Methods & Biostatistics. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Scientific Method, Correlation and Causation, Variables.
Can you give an example of Hypothesis?
If light intensity increases, then the rate of photosynthesis will increase until another factor limits.
What should I learn before Hypothesis?
Hypothesis is a Beginner topic, so no earlier topic is required. Other Beginner topics in Lab Methods & Biostatistics that pair well with it include Scientific Method, Variables, Control Group.
What topics are related to Hypothesis?
The closest topics to Hypothesis are Scientific Method, Correlation and Causation, Variables, Control Group. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Hypothesis?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Hypothesis. To practise the whole of Lab Methods & Biostatistics, use the Lab Methods & Biostatistics quiz.
How is Hypothesis different from Scientific Method?
Hypothesis: A testable explanation for an observation that can be supported or refuted by evidence. Scientific Method: A process of asking a question, forming a hypothesis, testing it with experiments and drawing conclusions. Read both side by side and note what each one explains.
What is a common mistake about Hypothesis?
A hypothesis is not just a guess or a question, and it is not the same as a theory.
How should I study Hypothesis step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Scientific Method and explain the difference aloud. Finally, take the Lab Methods & Biostatistics quiz and come back to this page for any question you miss.