4.3 Discrete Probability Distributions

Binomial DistributionSuccess or FailureProbability of EXACTLY x successes in n trialsP(x) = nCx(p)˄x(q)˄(n-x)P(x) = Binompdf(n,p,x)

Discrete Probability Distributions

Geometric DistributionProbability that the FIRST success is on the xth

trialP(x) = p(q)˄(x-1)P(x) = geometpdf(p,x)

Example

• The probability you will make a sale on a phone call is .23. Find the probability you will make your first sale on the 4th or 5th call.

Discrete Probability Distributions

Poisson DistributionThe probability of x OCCURRANCES in an interval P(x) = (μᵡe ᶹ)/x!

E≈2.72 2nd ln ˄ (1)Calculator: P(x) = ((μ˄x)e˄(-μ))÷x!P(x) = poissonpdf(μ,x)

Example

• The mean # of accidents per month at an intersection is 3. What is the probability that in any given month 4 accidents will occur here?

Example

• A population count shows that there is an average of 3.6 rabbits per acre living in a field. Find the probability that 2 rabbits are found on any given acre of the field.