due to different reasons so for example the home pricing you may contain some typos maybe you have some under priced sales because this happened between family members or maybe there was some fraud that happens so you know something that you can not predict because it's under price or maybe you have something over priced some cells that's big houses on some big island but you have very few samples of them so you can not find some interesting patterns not enough samples to learn anything interesting from London so how to deal with this kind of