I’m a transfer from a CC and older than most students so campus life isn’t as big of a factor for me as it would be if I were 18 but I am a little intimidated by the gender ratio at Rose-Hulman as a woman. Mostly wondering if Rose is enough better in bio for ~$30K in debt I wouldn’t have otherwise to be worth it and if not is there a big difference IUB and Purdue’s bio programs? I’ve seen that they seem to be neck and neck in rankings.
Rankings are subjective and unreliable…bordering on utterly stupid. Seriously, it’s like comparing an apple to an onion and calling one “better.” Just ignore them. I think the decision is a no-brainer. Go with the debt-free option. I’ll vote Purdue…they have a good basketball team 
Take one of your debt free options!!! If you were going for engineering, I would say Purdue in a heartbeat but for bio, I think it’s a toss up between Purdue and IU. As such, my vote would be Purdue (full disclosure, my D is in her second year there and we love the school).
Biology graduates do not have the highest pay prospects, so avoiding debt may be of higher priority with that major.
If you are pre-med, note that medical school is expensive, so taking undergraduate debt would just add on to the medical school debt that you would have if you do get into medical school.
Depending on your specific interest in biology, Purdue might make more sense or IU might make more sense. So spend some time with the course catalogues and take a look at research projects that different faculty members are engaged in.
And yes, for biology you really can choose the cheapest of these three and still get an excellent education.
Definitely go for Purdue or IU, Rose is really more of an engineering school (and debt free is always a good way to go).
Another vote for Purdue or IU. No reason to take on debt when you have excellent debt-free options.