Unify tables

[BorjaRuizReverter]

Table 1, 2 and 3 from tabela_1.md, tabela_2.md and tabela_3.md files are the right ones if compared with "Tabela 1", "Tabela 2" and "Tabela 3" from FindingPIbyLinearRegression notebook.

Actually, "Tabela 2" seems the only one that coincides.

So, we should replace Table 1 and Table 2 with "Tabela 1" and "Tabela 2", so that every table is the same.