Probability and Statistics Part 2

Keon Yong Lee
2 min readMay 4, 2020

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Independent Events

If two events are independent, the probability of one does not change if the other occurs. Mathematically,

However since above equation is not valid if P(B) = 0, we use a symmetric definition:

For multiple events,

Independent Trials

Binary Trials

Also called Bernoulli trials, it is a sequence of identical independent experiments such as repeated coin tossing. Given the probability of one event (p), the probability of the other event is 1 — p. The probability of a particular sequence of N trials with the k occurrences of the event with the probability p is:

Non-binary Trials

A set of outcomes for m-ary experiment is:

It has respective probabilities:

A particular sequence has respective occurrences of:

The probability of such sequence is:

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