Women who called auto-repair shops to inquire about getting a new radiator were quoted prices that averaged 6% higher than those offered to men, according to an experiment led by Meghan Busse of the Kellogg School at Northwestern University. Yet female callers who requested a price reduction were successful about 35% of the time, compared with just 25% for men. Shops may be caught off guard when women ask for discounts on car repairs, the researchers say.