Random Variables, Joint Distribution and Collecting Data

Question 1

What is a random variable

Answer 1

is real-valued function whose domain is the sample space. Where probability is the set of all subsets of the sample space, and the random variable is P(XeA)=P{S:X(S) e A}
The probability induces the distribution of x

Question 2

Discrete random variable is

Answer 2

One that can take on only a finite or countably infinite number of values

Question 3

Continuous random varialbe

Answer 3

A random variable that can take on any value in some interval, bounded or unbounded of the real line. A natural generalization (of different flavor)

Question 4

Binomial Random variable

Answer 4

How many successes in finite number of trials.

1. is made up of independent trials (each flip of a coin)
2. each trial can be classified as success or failure
3. Fixed number of trials
4. Probability of success (getting heads) is constant

Question 5

Hypergeometric random variable

Answer 5

Describes the number of successes in n trials where you’re sampling without replacement from a sample of size N whose initial probability of success was K/N
fx(x) =
(k
x)

Question 6

Point mass

Answer 6

each point of probability on a graph