Probability Basic Idea

PROBABILITY

Zafer AMInstitute Of Management Kerala

Karyavattom Campus

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What Is Probability ?

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What Is Probability ?Probability is a measure or

estimation of how likely it is that something will happen or that a statement is true.

Ways in FavourTotal Number Of Ways

Total Number Of Ways > Ways in Favour

Probability is b/w 0 & 1.12/10/2013

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If P=0 , Impossible Event.

If P=1 , Certain Event.definite

going to happen

0 < P <1

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Probability Of Not Happening

=

An Event P(A)

Event Going To Happen P(A)+Event Not Going To Happen P(A) = 1

Universe

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E1- Guyz eating SamosaE2- Guyz Eating Cutlet

P(A or B) = P(A) + P(B) - P(A∩B)

P(A) P(B)

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Mutually Exclusive Events

Two events are mutually exclusive if they cannot occur at the same time.An example is tossing a coin once, which can result in either heads or tails

P(A or B) = P(A) + P(B)

P(A) P(B)

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Probability Of Both Happening P(A) + P(B)

Atleast One Going To HappenP(A) + P(B) – P(A∩B) 

Probability Of Exactly One Happening.

P(A) or P(B)

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COINS

Heads Or Tails.Probability of getting Heads = ½Probability of getting Tails = ½

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Coins

Probability of getting one Heads and one Tail when 2 coin are tossed.

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{HH,HT,TH,TT} = 2/4 = 1/2

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What is the Probability for getting 3 heads and 1 tail if 4 coins are tossed ?

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Probabllity of hetting atleast 2 Head when

Tossing 3 coins.

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Multiplication TheoremThe probability of happening an event

can easily be found using the definition of probability.

But just the definition cannot be used to find the probability of happening of both the given events.

A theorem known as “Multiplication theorem” solves these types of problems.

P(A∩B) = P(A) * P(B|A) P(A|B) denotes the conditional probability of A assuming B.12/10/2013

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ReferenceWikipediawww.youtube.comhttp://www.mathsisfun.com

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