Discrete Random Variables Flashcards
0
Q
How would you work out cumulative distribution?
f(x) = P(X<=x)
A
Adding up the probabilities before a certain values, specified in the P(X<=x)
1
Q
What is the meaning of ∑x*P(X=x) ?
A
It is the mean:
Score * Probability
2
Q
How would you deal with E(aX)?
A
aE(X)
3
Q
How would you deal with E(aX+b)?
A
aE(X) + b
4
Q
How would you deal with Var(aX)?
A
a^2 * Var(X)
5
Q
How would you deal with Var(aX + b)?
A
a^2 * Var(X)
6
Q
What is a simplified formula for Var(X)?
A
E(X^2) - [E(x)]^2
7
Q
What is discrete uniform distribution?
A
A variable X is defined over a set of n distinct values.
e.g. P(X=x) = 1/n for all values of x.
(Basically… When all probabilities are equally likely - the same.)
