Probabilty

Question 1

Types of random variable

Answer 1

Discrete random variable

Continuous random variable

Question 2

What is discrete random variable

Answer 2

This is one which takes on only whole numbers (integer numbers)

Question 3

What is continuous random variable

Answer 3

It takes on values within an interval

Question 4

Probability distribution of discrete random variable

Answer 4

Y p(y) n(y) y(p(y) y^2 y^2py

To get p
Ncn x ncn

N(y)=p

While multiplying y(p(y)), only multiply the numerator
Eg 2x18/84 = 36/84

Question 5

Expected value

Answer 5

Exp(x)

Question 6

Variance

Answer 6

E(x)^2 = Ex^2p(x)

Question 7

To find what’s in the squares on joint distribution

Answer 7

Eg
1 2 3
A b c
0 0 3
0 1 2

First square = 3c3= 1

0 0 3
0 1 2
0 2 1
0 3 0
1 0 2
1 1 1
1 2 0
1 3 0

Question 8

Second table in joint distribution

Answer 8

Py
Yp(y)
Y2p(y)

Question 9

Variance in joint distribution

Answer 9

Ex^2p(x) - Exp(x)

Question 10

Covariance

Answer 10

E(xy) - e(x). E(y)