"press firmly to learn what your breasts feel like. a firm ridge in the lower curve of each breast is normal." this step for bse is not done unless you think you might have a breast lump.

This statement is false.
Whether you think you might have a breast lump or not, you should learn how to properly check your breasts so as to avoid any danger of lumps. Even though you may not feel anything, it is good to perform this routine check up once in a while.

To be honest, here's what i think. i think the answer is (and i'm not exactly sure), that it is, both personal and household income.