ANOVA (Analysis of Variance)

Learn about one-way and two-way ANOVA tests.

ANOVA (analysis of variance) is a statistical method used to compare the means of three or more groups or populations, one of which is the dependent variable. It is used to determine whether the differences between the averages of the groups are statistically significant or stem from luck. ANOVA and Student’s t-tests probe into the same issue. The difference between them is that the t-test analyzes differences between two groups, while ANOVA does it between three groups or more.

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One-way ANOVA

We use different variations of ANOVA in different circumstances. In a one-way ANOVA, there is only one independent categorical variable. The goal is to determine if the means of the dependent variables are affected by the independent variable.

Assume that we analyze the longevity of three different smartphone products. We have three sets of data available for each brand, and each dataset contains records of the time elapsed between the sale of a product and the end of its use. Our goal is to find if the brands are distinguishable from each other in terms of product lifetime. In such a situation, we use the one-way ANOVA.

To conduct an ANOVA in R, the aov() function is used. The function takes three arguments:

  • Dependent variable
  • Independent variable
  • Data name
aov(<dependent variable> ~ <independent variable>,<name of
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