Expectation Flashcards
Properties of expectation
- If k is a constant then E(k)=k
Hyper geometric distribution
It is a discrete probability distribution that models the selection of n observations without replacements from a finite population of size n where each outcome is either a success or failure
Hyper geometric distribution
Mean= nk
—-
N
Variance = N-n. N.k/N
——
N-1
(1-k/N)
PDF= (k/k) (N-k/n-k)
———————
N/n
Geometric distribution
The number of trials before the first success in n Bernoulli trials
Geometric distribution
F(x) = (1-p)^x-1 p
F(x)= q^x-1 p
Where q+p=1
P= success Q= failure
Mean= 1/p. Expected number of misses
Variance =
Uses of geometric distribution
It is used for cost benefit analysis
It is used in sports
In time managemente
Poison distribution
It is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time or space if this event occurred with a known average rate and independently of the time since the last event
Poisson distribution formula
P(x)= ¥^xE^-¥
————
X!
A binomial distribution is
One that has 2 outcomes either you fail or pass
We regard p as and q as
Sucess failure
P+q=q
1-p=q
Characteristics of binomial
It has n trials each trial results a success or failure
The probability of sucess is constant throughout the experiment
The number of trials are independent
Formula for binomial
F(x)= ncx p^x q^n-x
Mean np
Variance npq
Negative binomial
Model’s the number of trials before a specified number of sucesses