Difference between Null Hypothesis and Alternative Hypothesis

Difference between Null Hypothesis and Alternative Hypothesis

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Vikram
Vikram Singh
Assistant Manager - Content
Updated on Oct 13, 2023 15:30 IST

Null hypothesis and alternative hypothesis are the assumptions made by researchers to prove or disprove those assumptions. In this article, we will explore the difference between null and alternative hypothesis.

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When doing research, researchers or scientists make some assumptions regarding their research and then try to prove or disprove those assumptions. These assumptions are also termed hypotheses, and there are different types of hypotheses that are made during the research, and we will discuss them later. In this article, we will learn what is Null and alternate hypotheses and the differences between them on the basis of different parameters. Null hypothesis and alternative hypotheses are two mutually exclusive statements about population. Researchers perform tests on sample data to determine whether to accept or reject the hypothesis.

Table of Content

Null Hypothesis vs. Alternative Hypothesis

Parameter Null Hypothesis Alternative Hypothesis
Definition A null hypothesis is a statement in which there is no relation between the two variables. An alternative hypothesis is a statement in which there is some statistical relationship between the two variables.
What is it? Generally, researchers try to reject or disprove it. Researchers try to accept or prove it.
Testing Process Indirect and Implicit Direct and Explicit
p-value Null hypothesis is rejected if the p-value is less than the alpha-value; otherwise, it is accepted. An alternative hypothesis is accepted if the p-value is less than the alpha-value otherwise, it is rejected.
Notation H0 H1
Symbol Used Equality Symbol ( =, >=, <=) Inequality Symbol ( !=, <, >)
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What is a Null Hypothesis?

A statistical hypothesis in which there is no relationship between two variables (or a set of variables) is called a null hypothesis. 

  • It is represented by H0
  • It states that the population parameter is equal to the assumed (hypothesized) value.
  • A null Hypothesis is an initial claim by researchers using their specialized knowledge or domain expertise.
  • Generally, researchers want to disprove or reject the null hypothesis.

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What is an Alternative Hypothesis? 

A statistical hypothesis that states that there is a significant two variable (or set of variables) is called an Alternative Hypothesis.

  • It is represented by H1.
  • It is also referred to as a hypothesis other than a Null Hypothesis.
  • The alternative hypothesis states that a population parameter is smaller, greater, or different from the assumed value.
  •  It is what the researcher believes to be true or tries to prove it.

Note: 

  • Alternative and Null Hypotheses are complementary to each other.
  • Both the hypotheses are also exhaustive and mutually exclusive, i.e., together, both will cover every possible outcome, but only one can be true at a time.

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Examples of Null and Alternate Hypothesis

Problem Statement 1: Does eating an apple daily ensure weight loss? State both Null and Alternative hypotheses.

Answer:

Null Hypothesis (H0): Eating apples daily does not affect weight loss.

Alternative Hypothesis (H1): Eating apples affects weight loss.

Problem Statement 2: A researcher wants to know if the height of students at school differs from the national average of 5.5 feet. State null and alternative hypothesis.

Answer:

Here, researchers are interested in determining whether the height of students is either less than or greater than the national average height.

H0: average = 5.5 feet

H1: average != 5.5. feet

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Key Differences and Similarities Between Null Hypothesis and Alternative Hypothesis

  • In the Null Hypothesis, there is no relation between two variables, while in the Alternative Hypothesis, there is some statistical significance between the variables.
  • The result of the null hypothesis indicates no change in opinion, while the result of the alternative hypothesis causes a change in opinion.
  • In the null hypothesis, independent variables do not affect the dependent variable, while in the alternative hypothesis independent variable affects the dependent variable.
  • Researchers try to disprove the null hypothesis and prove the alternative hypothesis.
  • The null hypothesis is accepted if the p-value is greater than the alpha-value, while Alternative Hypothesis is accepted if the p-value is less than the alpha-value.
  • Both null and alternative hypothesis makes a claim about the population.
  • Both hypotheses are evaluated by statistical tests such as z-test, t-test, chi-square test, ANOVA, correlation, regression, etc.

Conclusion

In this article, we have learned what is Null Hypothesis and Alternative Hypothesis and the difference between them on the basis of different parameters.

A null hypothesis is a statement in which there is no relation between the two variables, while an alternative hypothesis is a statement in which there is some statistical relationship between the two variables.

Hope you will like the article.

Happy Learning!!

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FAQs

What is a Null Hypothesis?

A null hypothesis is a statement in which there is no relation between the two variables. It is represented by H0.

What is an Alternate Hypothesis?

An alternative hypothesis is a statement in which there is some statistical relationship between the two variables. It is represented by H1 or Ha.

Why Null and Alternate Hypothesis are important?

Null and Alternate hypotheses are very important as they help researchers to formulate the testable hypothesis (or research question), design experiments or studies, and make statistical inferences about population based on sample data.

What is the difference between null and alternate hypothesis?

In the Null Hypothesis, there is no relation between two variables, while in the Alternative Hypothesis, there is some statistical significance between the variables. The result of the null hypothesis indicates no change in opinion, while the result of the alternative hypothesis causes a change in opinion. In the null hypothesis, independent variables do not affect the dependent variable, while in the alternative hypothesis independent variable affects the dependent variable.

About the Author
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Vikram Singh
Assistant Manager - Content

Vikram has a Postgraduate degree in Applied Mathematics, with a keen interest in Data Science and Machine Learning. He has experience of 2+ years in content creation in Mathematics, Statistics, Data Science, and Mac... Read Full Bio