Final answer:
Mia's belief in a walking speed difference between upper and lower Manhattan residents is an example of an 2) illusory correlation, a cognitive bias where perceived associations are believed without supporting data.
Step-by-step explanation:
Mia's observations that people from upper Manhattan walk faster while those from lower Manhattan walk slower are likely influenced by an illusory correlation. This is a cognitive error where she perceives a relationship between two variables that statistically isn't there. It is a common mistake our brains make, where we accept information based on unsystematic observations or biased personal experiences, instead of empirical evidence.
People often assume correlations based on their own mental models of how the world works, not considering that their perspectives are shaped by media, personal experiences, and possibly confirmation bias, where evidence supporting preconceived ideas is favored over evidence that contradicts them.