확률 및 통계 3강 Youtube에서 시청가능합니다.
2.2 Definition of RV(Random Variable, 확률변수)
1) RV(Random Variable): real numbers mapped with each outcome of random experiment
EX) tossing a coin
- 앞면(H)이 나올 경우 1 mapping → H=1
- 뒷면(T)이 나올 경우 0 mapping → T=0
- P(T)=P(0)=1/2
- P(H)=P(1)=1/2
2) 지금부터 probability를 function화
- probability: P(A)에서 A는 event, case에 대한 확률을 의미
- function f(x): 확률을 숫자로 mapping
EX) tossing two coins
- RV: number of heads(앞면) ⇒ 0, 1, 2
3) by the conventional notation of RV
- X, Y, Z : set of x
- x, y, z : a specific value of X
2.3 Event defined by RV
1) Let “Ax” be an event
2.4 Distribution Function
1) for an RV x and a real number x, Cumulative Distribution(CDF) is defined like below picture.
2) features of CDF
- EX 2.3
2.5 Discrete RV
1) discrete: non- continuous
2) Probability Mass Function(PMF)
3) graph of Probability Mass Function(PMF) & Continuous Distribution Function(CDF)
3) delta(x) function
EX) 2 coins tossing
