Normalized tables specify a systematic structure for data with each fact relationship appearing only once. For instance, the Item Master carries Item attributes and any calculation or report that needs them will query this table.
Normalized data eliminates fact inconsistencies and ensures calculations on a field can be performed in a single column. This both speeds up and simplifies calculation logic. The oft-found alternative to normalized tables, matrices, are never used for calculation or data storage but instead generated where required with pivot tables.