The Hypothesis in Academic Writing
One of the most crucial aspects of the scientific method, the hypothesis is a written statement that can be scientifically tested. It explains the researcher’s reasoning and predicts what their research will find. It offers a tentative answer to a research question that has not yet been tested.
A hypothesis, however, is not a mere guess. It is based on existing theories and the researcher’s knowledge of the topic. A valid hypothesis is testable—which means the researcher can support it through research methods such as observation, experimentation, and statistical analysis of data. Some research projects require multiple hypotheses that address different aspects of the research question.
For example, if the researcher has noticed that leaves that don’t receive sunlight die, their hypothesis might be “leaves need sunlight to survive.” From there, they can begin experimenting to test this hypothesis. This can be done by covering a single leaf with foil for a period of five days and then recording the results to see the difference between the foil-covered leaf and the others.
Variables in a Hypothesis
In any kind of research, variables are elements that will be tested by the researcher. Variables can be anything testable and observable—events, objects, concepts, ideas, feelings, time periods, etc; they are of two types—dependent and independent.
A dependent variable, as the name suggests, is something that depends on other factors. A test score, for instance, can be a dependent variable because it depends on several factors like how much the student studied, how much sleep they got the night before the test, and how well they know the subject.
An independent variable stands alone without being influenced by other factors. A person’s age, for instance, can be an independent variable because it cannot be changed by other variables such as how much they eat or how many hours they sleep every day.
Researchers generally look for some sort of relationship between variables, which is to say they are trying to see if the independent variable causes some kind of change in the dependent variable.
5 Stages of Writing a Hypothesis
The process of writing a hypothesis can be divided into five stages:
1. Asking a Question
The first step of the scientific method is to ask a research question. The question must be specific and open to research within the constraints of the research project. Most research questions are framed using the words who, what, where, when, why, or how.
For example:
- How long does it take for tomatoes to grow?
- How did humans evolve from apes?
- Why are summer days longer than winter days?
- Can plants survive without sunlight?
2. Conducting Preliminary Research
The answer to the research question should initially be based on what is already known about the topic. The researcher should explore the existing body of knowledge in order to form informed assumptions about what their research will discover. This is the stage where they need to construct a conceptual framework to identify the variables they will study and the relationships between those variables.
During this stage, the researcher should take care not to be deterred by conflicting research that might contradict their hypothesis. Instead, they should use their findings to frame potential rebuttals and address all possible concerns.
3. Identifying All Variables
Once the researcher has a fair idea of what their hypothesis will be, they need to identify the dependent and independent variables they will work with. It is necessary to keep the constraints of the research project in mind before finalizing the hypothesis.
4. Formulating the Hypothesis
Once the preliminary research has been done and variables identified, it is time to formulate the answer to the research question. The researcher needs to think about how to answer the question and defend their position. For example, their research question may be posed as follows:
How does lack of sunlight affect plant growth?
As they begin their observations and data collection, they will find that lack of sunlight does not allow plants to grow, reproduce, and survive. Plants that have no access to sunlight will eventually lose their color and die. They will grow upward more rapidly than usual in their quest for light. This research, along with the body of experiments done on photosynthesis, can be used to answer the research question.
5. Refining the Hypothesis
A hypothesis must be precisely worded and testable. While there are many ways of phrasing a hypothesis, it should contain only clearly defined terms. A hypothesis must also contain the relevant variables, the specific group that is being studied, as well as the predicted outcome of the analysis or experiment.
Types of Hypotheses
1. Simple Hypothesis
Also known as a “basic hypothesis,” a simple hypothesis demonstrates the relationship between an independent variable (known as the “cause”) and a dependent variable (known as the “effect”).
For example:
The lack of sunlight causes plants to die.
Here, the cause is lack of sunlight and the effect is plants dying.
2. Complex Hypothesis
A complex hypothesis consists of several dependent and independent variables. Unlike a simple hypothesis, it demonstrates a relationship between multiple variables.
For example:
The lack of sunlight causes plants to die, which in turn reduces the amount of breathable air in the atmosphere.
3. Empirical Hypothesis
Also known as a “working hypothesis,” it is an assumption made during the stage of formulating a hypothesis. This changes when the assumption is tested using observation and experimentation.
For example:
Trees that get organic fertilizers produce tastier fruit than those that get chemical fertilizers.
4. Null Hypothesis
Unlike the empirical hypothesis, the null hypothesis claims there is no relationship between the dependent and the independent variables. The researcher must put forth an alternate hypothesis that can explain the phenomenon and then work to reject, nullify, or disprove the null hypothesis.
For example:
Sunlight does not affect the growth of plants.
5. Alternative Hypothesis
Also known as a “maintained hypothesis” or a “research hypothesis,” this is a collection of proposed hypotheses that are all discarded in favor of the most efficient one.
6. Logical Hypothesis
A logical hypothesis is a postulation or theory that cannot be tested but has some logical basis to support it. It can sometimes be converted into an empirical hypothesis by testing, observing, or experimenting with the proposed hypothesis.
For example:
Dinosaurs probably had green scales because the alligators, to whom they are closely related, have green scales.
The above hypothesis cannot be tested because dinosaurs are extinct. In order to prove or disprove the hypothesis, the researcher can only rely on logic and not empirical data.
7. Statistical Hypothesis
A statistical hypothesis uses representative statistical models to draw inferences about larger datasets. Statistical research is necessary when it is difficult or impossible to assess every single case.
For example:
Aloe vera plants need less water than lavender plants.
In the above example, it would be impossible for the researcher to study every aloe vera and lavender plant in the world. But they can observe a limited number of samples in order to predict with high probability that the results of the study would remain stable across the entire population.
8. Associative and Causal Hypothesis
An associative hypothesis postulates a connection between two variables but does not seek to explore whether one variable has a direct impact upon the other.
For example:
A large number of smokers had to be hospitalized for lung cancer. (This does not mean that the hospital made them sick.)
A causal hypothesis, on the other hand, not only postulates a connection between two variables, but it also predicts that changes in one variable will cause changes in the other.
For example:
A hike in the price of gas increases the number of people who take public transport to work.
9. Directional and Non-directional Hypothesis
A directional hypothesis predicts the negativity or positivity of the effect of the independent variable on the dependent variable before the test is conducted.
For example:
Charging grocery store customers 10 cents for plastic bags will increase the sales of reusable bags.
A non-directional hypothesis does not predict the negativity or positivity of the effect of the independent variable on the dependent variable before the test is conducted.
For example:
Charging grocery store customers 10 cents for plastic bags will lead to a change in sales of reusable bags.
Coming up with the right hypothesis for a research question is an undeniably vital part of a study or experiment. Following all the steps involved in addition to choosing the most suitable type of hypothesis ensures that a researcher is sufficiently prepared for the next steps of the scientific method.
