Slytherin is /ourhouse/.

Reminder that it's empirically proven that pure-blooded wizards correlate with higher levels of IQ and that pure-bloods score much higher on OWLs and NEWTs compared to students that half-blood, muggle-born or raised in muggle families. Ever notice how in recent times the Ministry of Magic has been pushing hard for acceptance of muggles and praising wizards that have relationships with them? Or the fact that Wizarding schools have suddenly started introducing nonsense subjects like "muggle studies"?

b-but my best friend is muggle-born and she's the smartest in my class!

Cognitive bias, also the exception does not prove the rule. Remember Hermione Granger? Turns out she was secretly having sexual affairs with jewish muggles behind closed doors, a certain Weinstein fellow being one of them, to get ahead in western nations. So I wouldn't use her as an example if that's what you were thinking.