SRS Review
Q1: Suppose we have 6 people named A, B, C, D, E and F and we take an SRS of size 2.
What is P(A in sample) = ?
How about P(C and D in sample) = ?
A:
AB, AC, AD, AE, AF
BC, BD, BE, BF
CD, CE, CF
DE, DF
EF
P(CD) = 1/15
P(A) = 1/3
Q2: We have two classrooms: D8 and D100. D8 has 10 students not named Sam. D100 has 4 students, one is named Sam. Suppose we flip a fair coin to pick a classroom, then take a SRS of size 1.
P(D8|Sam) = ?
P(D8|no San) = ?
A:
P(D8|Sam) = 0
P(D8|no Sam) = P(D8 ∩ no Sam) / P(no Sam) = 4/7
P(D8 ∩ no Sam) = (0.5)(1) = 0.5
P(no Sam) = P(D8 ∩ no Sam) + P(D100 ∩ no Sam) = (0.5)(1) + (0.5)(3/4) = 7/8
'Computer Science 🌋 > Machine Learning🐼' 카테고리의 다른 글
| Pandas part 2 Review (0) | 2023.05.27 |
|---|---|
| Pandas part 1 Review (0) | 2023.05.26 |
| Feature Engineering (0) | 2023.05.25 |
| Canonicalization (0) | 2023.05.24 |
| Regex (0) | 2023.05.24 |
