How to Write a Null and Alternative Hypothesis: A Guide with Examples

When undertaking a qualitative or quantitative research project, researchers must first formulate a research question, from which they develop a hypothesis. By definition, a hypothesis is a prediction that a researcher makes about the research question and can either be affirmative or negative. In this case, a research question has three main components: variables (independent and dependent), a population sample, and the relation between the variables. When the prediction contradicts the research question, it is referred to as a null hypothesis. In short, a null hypothesis is a statement that implies there is no relationship between independent and dependent variables. Hence, researchers need to learn how to write a good null and alternative hypothesis to present quality studies.

General Aspect of Writing a Null and Alternative Hypothesis

Students with qualitative or quantitative research assignments must learn how to formulate and write a good research question and hypothesis. By definition, a hypothesis is an assumption or prediction that a researcher makes before undertaking an experimental investigation. Basically, academic standards require such a prediction to be a precise and testable statement, meaning that researchers must prove or disapprove it in the course of the assignment. In this case, the main components of a hypothesis are variables (independent and dependent), a population sample, and the relation between the variables. Therefore, a research hypothesis is a prediction that researchers write about the relationship between two or more variables. In turn, the research inquiry is the process that seeks to answer the research question and, in the process, test the hypothesis by confirming or disapproving it.

How to write a null and alternative hypothesis

Types of Hypotheses

There are several types of hypotheses, including an alternative hypothesis, a null hypothesis, a directional hypothesis, and a non-directional hypothesis. Basically, the directional hypothesis is a prediction of how the independent variable affects the dependent variable. In contrast, the non-directional hypothesis predicts that the independent variable influences the dependent variable, but does not specify how. Regardless of the type, all hypotheses are about predicting the relationship between the independent and dependent variables.

What is a Null and Alternative Hypothesis

A null hypothesis, usually symbolized as “H0,” is a statement that contradicts the research hypothesis. In other words, it is a negative statement, indicating that there is no relationship between the independent and dependent variables. By testing the null hypothesis, a researcher can determine whether the inquiry results are due to the chance or the effect of manipulating the dependent variable. In most instances, a null hypothesis corresponds with an alternative hypothesis, a positive statement that covers a relationship that exists between the independent and dependent variables. Also, it is highly recommendable that a researcher should write the alternative hypothesis first before the null hypothesis.

10 Examples of Research Questions with H0 and H1 Hypotheses

Before developing a hypothesis, a researcher must formulate the research question. Then, the next step is to transform the question into a negative statement that claims the lack of a relationship between the independent and dependent variables. Alternatively, researchers can change the question into a positive statement that includes a relationship that exists between the variables. In turn, this latter statement becomes the alternative hypothesis and is symbolized as H1. Hence, some of the examples of research questions and hull and alternative hypotheses are as follows:

1. Do physical exercises help individuals to age gracefully?

A Null Hypothesis (H0): Physical exercises are not a guarantee to graceful old age.

An Alternative Hypothesis (H1): Engaging in physical exercises enables individuals to remain healthy and active into old age.

2. What are the implications of therapeutic interventions in the fight against substance abuse?

H0: Therapeutic interventions are of no help in the fight against substance abuse.

H1: Exposing individuals with substance abuse disorders to therapeutic interventions helps control and even stop their addictions.

3. How do sexual orientation and gender identity affect the experiences of late adolescents in foster care?

H0: Sexual orientation and gender identity have no effects on the experiences of late adolescents in foster care.

H1: The reality of stereotypes in society makes sexual orientation and gender identity factors complicate the experiences of late adolescents in foster care.

4. Does income inequality contribute to crime in high-density urban areas?

H0: There is no correlation between income inequality and incidences of crime in high-density urban areas.

H1: The high crime rates in high-density urban areas are due to the incidence of income inequality in those areas.

5. Does placement in foster care impact individuals’ mental health?

H0: There is no correlation between being in foster care and having mental health problems.

H1: Individuals placed in foster care experience anxiety and depression at one point in their life.

6. Do assistive devices and technologies lessen the mobility challenges of older adults with a stroke?

H0: Assistive devices and technologies do not provide any assistance to the mobility of older adults diagnosed with a stroke.

H1: Assistive devices and technologies enhance the mobility of older adults diagnosed with a stroke.

7. Does race identity undermine classroom participation?

H0: There is no correlation between racial identity and the ability to participate in classroom learning.

H1: Students from racial minorities are not as active as white students in classroom participation.

8. Do high school grades determine future success?

H0: There is no correlation between how one performs in high school and their success level in life.

H1: Attaining high grades in high school positions one for greater success in the future personal and professional lives.

9. Does critical thinking predict academic achievement?

H0: There is no correlation between critical thinking and academic achievement.

H1: Being a critical thinker is a pathway to academic success.

10. What benefits does group therapy provide to victims of domestic violence?

H0: Group therapy does not help victims of domestic violence because individuals prefer to hide rather than expose their shame.

H1: Group therapy provides domestic violence victims with a platform to share their hurt and connect with others with similar experiences.

Summing Up on How to Write a Null and Alternative Hypothesis

The formulation of research questions in qualitative and quantitative assignments helps students develop a hypothesis for their experiment. In this case, learning how to write a good hypothesis that helps students and researchers to make their research relevant. Basically, the difference between a null and alternative hypothesis is that the former contradicts the research question, while the latter affirms it. In short, a null hypothesis is a negative statement relative to the research question, and an alternative hypothesis is a positive statement. Moreover, it is important to note that developing the null hypothesis at the beginning of the assignment is for prediction purposes. As such, the research work answers the research question and confirms or disapproves of the hypothesis. Hence, some of the tips that students and researchers need to know when developing a null hypothesis include:

  • Formulate a research question that specifies the relationship between an independent variable and a dependent variable.
  • Develop an alternative hypothesis that says a relationship that exists between the variables.
  • Develop a null hypothesis that says a relationship that does not exist between the variables.
  • Conduct the research to answer the research question, which allows the confirmation of a disapproval of a null hypothesis.