Probability & Permutation
-The n factorial is defined as the product of the integers from 1 to n.
-It can be written as "n!". This means that we are looking for (n)(n-1)(n-2)(n-3)...(3)(2)(1)
N.B: Two numbers containing factorials and being divided by one another does not mean they can be simplified: 10!/5!=/=2!
Permutation ( Ordered Arrangement)
Using factorial notation: n objects can be arranged in "n!" ways.
Theorem for number of permutations (with no repetitions):
nPr=n(n−1)(n−2)...(n−r+1)=n!/(n−r)!When there is repetition, it is possible to assign different "n"s for each.This results in a new formula:
The sample space is the set of all possible outcomes of the experiment.The Event (E) is a subset of the sample space.
P(E)=r/n where r is the number of ways for a specific outcome and n is the number of all outcomes. This is to determine the success of an event or its occurrence.
To determine non-occurrence: P(E/)= 1-r/n
The sum of the probabilities in any experiment is equal to 1.
the probability of an even ranges between 0 and 1. if the event's occurrence is impossible, then the probability is 0, although absolute certainty means that the probability is 1.