Difference between Null Hypothesis and Alternative Hypothesis

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

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 different types of hypotheses are made during the research, and we will discuss them later. In this article, we will learn what null and alternate hypotheses are and the differences between them based on different parameters. Null hypothesis and alternative hypotheses are two mutually exclusive statements about population. Researchers test sample data to determine whether to accept or reject the hypothesis.

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Table of Content

• Null Hypothesis vs. Alternative Hypothesis
• What is a Null Hypothesis?
• What is an Alternative Hypothesis?
• Example
• Key differences and similarities

Null Hypothesis vs. Alternative Hypothesis

What is a Null Hypothesis?

A statistical hypothesis in which no relationship exists 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.

Read Also: Skewness in Statistics

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

Read Also: Conditional Probability

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Key Differences and Similarities Between Null Hypothesis and Alternative Hypothesis

• In the Null Hypothesis, there is no relation between the 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, the 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 the 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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