How to write a hypothesis

Writing a hypothesis starts with a research question that you want to answer. The question should be focused, specific, and researchable within the constraints of your project.

  • Do students who attend more lectures get better test results?

Do some preliminary research

Your initial answer to the question should be based on what is already known about the topic. Look for previous theories and studies to help you form educated guesses about what you will find in your research.

At this stage, you can build a conceptual framework to identify which variables you will study and what you think are the relationships between them.

Formulate your hypothesis

You should now have an idea of ​​what you expect to find. Write your initial answer to the question in a clear and concise sentence.

  • Attending more lectures leads to better exam results.

Refine your hypothesis

You want to make sure that when you learn how to write a hypothesis that it is specific and testable. There are several ways to formulate a hypothesis, but all the terms you use must have clear definitions, and the hypothesis must contain:

  • The relevant variables
  • The specific group being studied.
  • The expected result of the experiment or analysis.

Express your hypothesis in three ways

To identify the variables, you can write a simple prediction. The first part of the sentence states the independent variable and the second part states the dependent variable.

  • If a freshman starts attending more lectures, their test scores will improve.

In academic research, hypotheses are most commonly expressed in terms of correlations or effects, where the predicted relationship between variables is directly stated.

  • The number of lectures freshmen attend has a positive effect on their test scores.

If you are comparing two groups, the hypothesis can indicate what difference you expect to find between them.

  • Freshmen who attended the most lectures will have better test scores than those who attended few lectures.

Write a null hypothesis

If your research involves statistical hypothesis testing, you will also need 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 H 0 , while the alternative hypothesis is H 1 or H a .

  • H 0 : The number of lectures freshmen attend has no effect on their final exam scores.
  • H 1 : The number of lectures attended by freshmen has a positive effect on their final exam scores.

Tips to learn how to write a hypothesis

Our staff scientists offer the following tips for thinking and writing good hypotheses.

  • The question comes first.  Before formulating a hypothesis, you must clearly identify the question you are interested in studying.
  • A hypothesis is a statement, not a question. Your hypothesis is not the scientific question in your project. The hypothesis is an educated and testable prediction about what will happen.
  • Make it clear. A good hypothesis is written in clear and simple language. Reading your hypothesis should tell a teacher or judge exactly what you thought was going to happen when you started your project.
  • Keep the variables in mind. A good hypothesis defines variables in easy-to-measure terms, such as who the participants are, what changes during the test, and what the effect of the changes will be.
  • Make sure your hypothesis is “testable.” To prove or disprove your hypothesis, you need to be able to do an experiment and take measurements or make observations to see how two things (your variables) are related. You should also be able to repeat your experiment over and over again, if necessary.

How to Write a “Testable” Hypothesis: Make sure you’ve done all of these things:

  • You thought about what experiments you will need to perform to make the test.
  • You identified the variables in the project.
  • The independent and dependent variables were included in the statement of the hypothesis. (This helps ensure your statement is specific enough)
  • Do your research. Many studies similar to yours may have already been done. What you learn from the research and available data can help you shape your project and hypothesis.
  • Don’t bite off more than you can chew! Answering some scientific questions may involve more than one experiment, each with its own hypothesis. Make sure your hypothesis is a specific statement related to a single experiment.

Examples of how to write a hypothesis

research question Hypothesis null hypothesis

What are the health benefits of eating an apple a day? Increased apple consumption in those over 60 will result in decreased frequency of doctor visits. Increasing apple consumption in people over 60 will have no effect on the frequency of visits to the doctor.

Which airlines have more delays? Low-cost airlines are more likely to experience delays than premium airlines. Low-cost and premium airlines are just as likely to experience delays.

Can flexible work arrangements improve job satisfaction? Employees who have flexible work schedules will report higher job satisfaction than employees who work fixed hours. There is no relationship between the flexibility of working hours and job satisfaction.

How effective is high school sex education in reducing teen pregnancy? Adolescents who received sex education lessons in high school will have lower rates of unplanned pregnancy than adolescents who did not receive any sex education. Sex education in high school has no effect on teen pregnancy rates.

What effect does the daily use of social networks have on the attention span of children under 16 years of age? There is a negative correlation between the time spent on social networks and attention span in children under 16 years of age. There is no relationship between the use of social networks and attention span in children under 16 years of age.

How to write a hypothesis in history

Throughout history, scientists have formulated hypotheses and then set out to prove or disprove them. Scientific experiments become a dialogue between scientists and that hypotheses are rarely (if ever) “eternal”.

In other words, even a proven hypothesis can be displaced by the next research group on a similar topic, whether the research appears a month or a hundred years later.

A look at the work of Sir Isaac Newton and Albert Einstein, more than 100 years apart, shows good hypothesis writing in action.

A hypothesis is a possible explanation of something that is observed in nature. For example, it is a common observation that objects thrown into the air fall to the ground. Sir Isaac Newton (1643-1727) put forward a hypothesis to explain this observation, which could be expressed as ‘objects with mass are attracted to each other through a gravitational field.

Newton’s hypothesis demonstrates the techniques for writing a good hypothesis: it is testable. It is simple. It’s universal. It allows predictions that will occur in new circumstances.

It is based on previously accumulated knowledge.

Despite its incredible explanatory power, Newton’s hypothesis was wrong. Albert Einstein (1879-1955) provided a hypothesis closer to the truth, which can be expressed as ‘objects with mass that make space bend’.

This hypothesis discards the idea of ​​a gravitational field and introduces the concept of space as  flexible . Like Newton’s hypothesis, the one offered by Einstein has all the hallmarks of a good hypothesis.

That’s good news for scientists of all ages. There are always questions to answer and educated deductions to make! So you must learn how to write a hypothesis.

Alex Musk
Author: Alex Musk

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