It doesn't say "some women." It says "women can't read maps." I'd say it's more like "sweeping generalizations."
BTW, there are few landmarks when one is out at sea. Does the person who did the study suggest I count waves to get us back to port, say, "look for a wave that has a big pointy thing at the top & follow that one?"
Yes, that could be an acceptable description for a statistical "trend." It's a bell curve thing. People who use these methods and terms understand that there's a 10 to 20 percent population on either side of the norm who buck the "trend."