---
source: knowledge_base
topic: statistics
class_level: class_11
difficulty: intermediate
---

Statistics and Probability:
Mean=sum(x)/n. Variance=sum((x-mu)^2)/n. SD=sqrt(variance).
P(A∪B)=P(A)+P(B)-P(A∩B). P(A|B)=P(A∩B)/P(B).
Bayes: P(A|B)=P(B|A)*P(A)/P(B).
Binomial: P(X=k)=C(n,k)*p^k*(1-p)^(n-k).
CLT: sample means approach normal distribution as n increases.