ANOVA Notation
For one-way ANOVA, $y_{ij}$ denotes the $j$-th observation from treatment $i$, where $i = 1, \dots, k$ and $j = 1, \dots, n_i$.
The treatment mean is
$$ \bar{y}_{i\cdot} = \frac{1}{n_i}\sum_{j=1}^{n_i} y_{ij}, $$and the grand mean is
$$ \bar{y}_{\cdot\cdot} = \frac{1}{N}\sum_{i=1}^{k}\sum_{j=1}^{n_i} y_{ij}, \quad N = \sum_{i=1}^{k} n_i. $$This notation is the foundation for the ANOVA identity, sums of squares, and ANOVA table.