Introductory
Stat 212 Fall 2015
Class Info
STAT 212 DISCRETE PROBABILITY
Monday, Thursday 2:45  4:00pm @ HE 920
Office Hours: by appointment only.
Class Email: stat212.fall2015@gmail.com
Instructor Email: niki.xu@hunter.cuny.edu
Textbook and topics
Chapter 5
Independence
Independence
In everyday language, we describe two events
that have nothing to do with each other as
independent.
In statistics, independence is yet another
English word with precise statistical meaning.
Independence
Definition:
Discrete Probability
Chapter 3
Counting Procedures and Their Applications
Uniform Probability Model
Define: When simple events in a sample space have
equal probabilities, we have a uniform probability model.
P(event E ) = # outcomes in E
# outcomes in S
Chapter 6.1
Intro to Random Variables
Random Variables
Frequently, when an experiment is performed, we are interested
mainly in some function of the outcome as opposed to the
actual outcome itself.
For instance, in tossing dice, we are often interested
Joint Distrubutions
Often times we want to understand the behaviors of two
or more random variables in conjunction with each
other. We have come up with Joint Distributions to help
us see better the behaviors of the R.V.s side by side.
Joint probability
Chapter 7
Describing Random Variables and
Their Distributions
Mean
Example: in a quiz of 5 questions, the distribution of
correct score and their frequency presented below
# correct ans. 
0 1
# students
2 2 6 20 15 5

2
3
4 5
To compute the mean numbe
Discrete Probability
Chapter 2
Basic concepts of probability
STATISTICAL EXPERIMENTS
Gathering data  many ways
Socioeconomic surveys
Experiments in biology, physics, chemistry
Experiments and surveys in the health sciences
The Sample Space
Define: Sampl
Chapter 4.2
Conditional probability part 2
Conditional probabilities with stages
Example 5
Suppose you are attending a meeting of the Parents of
Twins. If you chose a family at random which has just
one pair of twins and no other children, what is the
pr