If you play normal unmodded lab rats, it's 10 points resistance gain for repeating an event.
Serum Effects...
Blue.. No boost to influence. If you repeat an event, it's 10 point increase in resistance.
Red.. +15 temporary boost to influence but is 1.5 times more resistance points. For normal, that is 15 points increase in resistance.
Purple... Lowers influence by 15 and is 0.5 of resistance points. For normal, that only raises your resistance by 5 points.
If she gets past 50 points resistance, she will begin refusing events. At 100 points, you're screwed! They only lose 1 point daily so if she's at 50 points, you need to wait 50 days for her to get back to 0 resistance.