#Probability#

• Conditional probability - P(A|B) / P(B|A) = P(A) / P(B) - the ration of area in a venn diagram
• if there are 30 people in a room the probability of a common birthday is close to 70%
• P(A ∩ B) = P(A) P(B|A) = P(A) . P(B)
• P(A ∪ B) = P(A) + P(B) - P(A ∩ B)

Binomial distribution

Random variable = count.

Probability is like measuring a frequency.

Expected value is sum of xi * pi = np for binomial distributions.

Poison distribution is binomial distribution tending towards inf.
An event can occur 0, 1, 2, … times in an interval. The average number of events in an interval is designated lambda.

• Insurance
• Gambling
• Sports