Difference Between ANOVA and ANCOVA

Difference Between ANOVA and ANCOVA

When it comes to ANOVA and ANCOVA, Both are used in statistics for assessing either one or multiple variables in a given sample, depending on the kind of analysis.

For statistical data analysis, ANOVA (Analysis of Variance) examines variance; while for such analysis, ANCOVA (Analysis of Covariance) investigates covariance. ANOVA requires us to know the variance of the data or sample, whereas ANCOVA requires us to know the statistical covariance of the sampled data.

The kind and nature of the data that is being investigated determines which approach to use.

What is ANOVA?

‘Analysis of Variance’ is the acronym for the process of analyzing data. Analyzing data with one or more variables is done using this statistical approach. It is used to compare the averages of two, three, or more variables in a sample.

In both the linear and non-linear models, it may be applied. If two or more population means are equal, ANOVA gives a statistical test that generalizes the t-test beyond two means. We may apply the ANOVA model by dividing the group’s differences into treatments..

ANOVA is a commonly used approach since it requires little effort and yields results quickly. Also, there are less possibilities of making a mistake. Agribusiness, psychology, and other fields often use it. It comes in a variety of shapes and sizes.

There are a variety of ANOVA models and kinds to choose from.

The different kinds of ANOVA

To examine the differences between two or more independent sets of data, one-way ANOVA is utilized.

This kind of ANOVA is used to examine the interactions between treatment groups (levels of a categorical independent variable).

Repetitive actions Using the same subject for each treatment, an ANOVA of this kind may be employed.

When there is more than one response variable, the multivariate analysis of variance, or MANOVA, is utilized.

  • One-Way ANOVA Models
  • Models with fixed effects.
  • Models based on chance events.
  • These are known as mixed-effects models.

What is ANCOVA?

For “Analysis of Covariance,” there is ANCOVA. Statistically, it is used to analyze a sample or group of samples of one or more variables using the Covariance. A linear connection between the dependent and independent variables is assumed.

Because it makes advantage of covariance, it has a higher level of statistical heft. In comparison to ANOVA, the calculation of ANCOVA is more complicated.

If the two variables (dependent and independent) are connected in a linear way, we may think of it as a combination of ANOVA and regression. In addition, the regression has resulted in a uniformity among them.

ANCOVA’s effectiveness and the quality of its output are entirely dependent on the data being analyzed. Different levels of dependent variables may be examined using ANCOVA.

In a nutshell, ANCOVA is a kind of ANOVA.

Difference Between ANOVA and ANCOVA

  • Both linear and non-linear models are used in ANOVA analyses of data. A generic linear model is all that is used by ANCOVA.
  • To use ANCOVA, we need to determine the covariance. However, covariance has no place in an ANOVA.
  • An analysis of variance (ANOVA) is a statistical method for determining the differences between two variables. However, ANCOVA is an ANOVA model.
  • In comparison to ANOVA, the ANCOVA is more impartial and trustworthy.
  • ANCOVA is more powerful than ANOVA because it uses covariance, while ANOVA does not utilize covariance.
  • ANOVA separates differences between groups based on their treatment. Treatment and covariate differences are separated in ANCOVA.
  • ANCOVA is a more complicated method of analyzing data than ANOVA, which is a simpler method.
  • In an ANCOVA, ANOVA and regression are combined into one analysis. As a result, it is preferred over ANOVA.

About ANOVA and ANCOVA: Frequently Asked Questions

Is a factorial ANOVA a two-way ANOVA?

Factorial ANOVA is a two-way ANOVA. It’s the main distinction that separates them:

If there is an interaction between the two independent variables, a two-way ANOVA may be used to determine it. Adding a new independent variable to the regression does nothing more than that.

However, factorial ANOVA is used to find the average of two or more independent variables. Adding one, two, or more more independent variables to the regression equation is all that this does.

What are the ANOVA underlying assumptions?

Anova’s assumptions include:

  • All groups have an equal distribution of the dependent variable.
  • Each group’s population has the same variance.
  • Samples that were drawn by themselves
  • Each sample has its own unique set of observations.

Do you know whether or not ANOVA is parametric?

The analysis of variance (ANOVA) may be non-parametric as well as parametric. It becomes parametric when used for score data, and non-parametric when used for ranking or order data.

In ANOVA, what does the P-value denote?

The likelihood of seeing a result in a statistical hypothesis test that is at least as severe as the actual observed result is referred to as the p-value.

In ANOVA, what is the alternative hypothesis to the null hypothesis?

One- and two-way Anova have distinct null hypotheses. The same will be the null hypothesis for All groups in a one-way ANOVA

In two-way ANOVA, there are three possible null hypotheses to consider:

  • The identical factor group observations provide the same results.
  • Means are the same regardless of how the data are organized.
  • Neither of the two components interacts with the other.
  • T-test and ANOVA are two different types of statistical tests.

It is possible to calculate the population mean differences between groups using both t-tests and ANOVAs. While ANOVA and t-test both investigate the difference between two groups’ mean values, the t-test is solely used to analyze this difference. ANOVA, on the other hand, resembles doing a series of t-tests. More than two groups may be analyzed.


In both ANOVA and ANCOVA, the statistical data or sample is analyzed using one or more variables. In contrast to ANOVA, ANCOVA employs the covariance to determine the findings of a study.

Both linear and non-linear models may be used with ANOVA to do research. A generic linear model is all that is used by ANCOVA in their research. ANCOVA is more trustworthy and impartial than ANOVA.

Because in ANCOVA, we first have to partition the treatment and covariate fluctuations and then compute the covariance, ANOVA does not need as much computation effort as ANCOVA.

Both ANOVA and regression are included in ANCOVA. Because it employs covariance and also combines ANCOVA and regression, ANCOVA is statistically more powerful, but we cannot use it all the time.

The optimal method for analyzing and drawing conclusions relies on the kind and nature of the data being analyzed. Statisticians can only provide us with data, but how we interpret that data is up to the individuals who use it.

That is, there are a variety of statistical methods that may be used to accomplish the same goal, and each one yields a different outcome. As a consequence, the most critical step in achieving the most accurate and beneficial outcomes is selecting the appropriate approach.

Even if ANCOVA is more powerful and trustworthy, we cannot assume that it offers us the best and most accurate results every time. For these and many other reasons, it is impossible to say with certainty whether or not a given set of findings is accurate.