While performing analysis of variance, the two types of variances which can occur in a data are: 

Key Points

• In the analysis of variance (ANOVA), two types of variances can occur in the data: between-group variance and within-group variance. The between-group variance represents the variability between the different groups or treatments being compared.
• It measures how different the group means are from each other. On the other hand, the within-group variance reflects the variability within each group and quantifies the spread of the observations within each group.
• ANOVA examines both these variances to assess whether the observed differences in the group means are statistically significant. 

Additional Information

• ANOVA (Analysis of Variance) is a statistical technique used to compare means between two or more groups or treatments. It assesses whether there are any significant differences in the means of the groups, indicating that there may be a relationship between the groups and the dependent variable being measured.
• The main objective of ANOVA is to partition the total variability observed in the data into different components to determine the relative contributions of different sources of variation. These sources of variation can be categorized into two main types: between-group variation and within-group (or within-treatment) variation.

Hence, while performing analysis of variance, the two types of variances which can occur in a data are between and within groups.