Analysis of variance (ANOVA)
- It is a statistical technique developed to study significance of difference between two or more than two sample means [ or equality of several means].
Assumptions of ANOVA
- The distribution of residual is normal.
- The data/samples are independent of each other and are taken at random.
- Each one of the populations has same variance.
- Variance are added or summed.
Characteristics of ANOVA
- The dependent variable must be continuous and independent variable must be categorical.
- Used in regression studies to determine the influence of independent variables on dependent variables.
- Variance is assumed to be constant.
- Adding and multiplying a constant to all observations doesn’t alter significance.
Note:
i) One-way ANOVA: When an independent factor ( Single factor) influences different sample groups.
ii) Two-way ANOVA: When two independent factors influence same sample groups.
Uses of ANOVA
- To support other statistical tools.
- To compare models with the objective of selecting samples that adequately describe the data.
- To test hypothesis about batches of coefficient.
- As a tool for summarizing complex high-dimensional inferences.