Thank you @twilightgalaxy and @cyberwulf for your responses. In that case, I take it that it is not necessary to contact professors or identify them in one's application.
Additionally, I am debating on retaking the GRE and I wanted some advice. Is it true that an applicant for Biostatistics PhD and MS programs must get above a certain GRE score or range of scores to be seriously considered, but scoring much higher than that will not necessarily help one's application much? I recently took it and got a 163V and 165Q. I am wondering if the 165Q would put me at a disadvantage for competitive Biostatistics PhD programs, particularly at Harvard / U Washington / Hopkins. I have a strong math background (4.0 GPA at top 25 school, math major with some grad statistics/biostatistics courses), but just not a particularly strong GRE quant score.