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Probability

Question

What is the formula of probability?

1 year ago

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29 Replies

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R

Rusty Botsford



29 Answers

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Let E be the set of all possible results of an experiment. We are also denote the results that are asked for/investigated as the set A.

Then the probability of the event A, which is having one of the results in the set A, is equal to (Number of elements in A) divided by (Number of all elements).


For example, say that we throw a die with a friend one-by-one. Our friend throws the die and gets a 1. If we get a 2, 3, 4, 5, or 6, we are winning this round. So, the results that we ask for is A={2, 3, 4, 5, 6} and all possible results are E={1,2,3,4,5,6}.


Hence, the probability that we win this round is (Number of elements in A) = 5, divided by (Number of all elements) = 6, which is 5/6.


If our friend had scored a 2, we would win if we scored a 3, 4, 5 or 6. Then the probability that we win would be (Number of elements in A) = 4, divided by (Number of all elements) = 6, which is 4/6 = 2/3.


If our friend had scored a 3, we would win if we scored a 4, 5 or 6. Then the probability that we win would be (Number of elements in A) = 3, divided by (Number of all elements) = 6, which is 3/6.


If our friend had scored a 4, we would win if we scored a 5 or 6. Then the probability that we win would be (Number of elements in A) = 2, divided by (Number of all elements) = 6, which is 2/6 = 1/3.


If our friend had scored a 5, we would win only if we scored a 6. Then the probability that we win would be (Number of elements in A) = 1, divided by (Number of all elements) = 6, which is 1/6.


Our friend cannot score a 0 because 0 does not appear on the die. Also, if our friend scores a 6, then we cannot win that round, because there is no larger number on the die, which would have allowed us to win.

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R
Roshan Sharma

Probability of a favourable event P(E) = (Number of favourable outcomes) ÷ (Number of Elements in Sample space). 

I
Inès Bentin

The most known formula of probability is division of the number of favorable events by the total number of possible events.

D
Dhimahi Shah

Think of it as a magical recipe where you count the number of ways your desired outcome can happen and divide it by all the possible outcomes in the universe of your experiment.


It's like making a potion—mixing the right ingredients for a successful outcome!


The mathematical formula for an event E is given as:


P(E)= (Total Number of Possible Outcomes) / (Number of Favorable Outcomes)




D
Diya Bhandari

Probability = (Number of a Favourable outcome) / (Total number of outcomes) P = n (E) / n (S) Where P is the probability, E is the event and S is the sample space.

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Probability of impossible event is zero. Probability of certain event is 1. And in general probability of an event = favourable cases for an event / total possible cases.

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M
Mohammad Abrar Biswas

number of objects in interest / total number of objects

A
Ajani Kehinde Azeez

P(E) = n(E)/n(s)

Where n(E) is number of points

n(s) is the number of sample

R
Rohan Das

No. Of favourable conditions divided by total no. Of outcomes

S
Sudip Bahadur Karki

The formula to find probability is Image result for what is the formula of probability of an event

A
Aqsa

Probability = (Number of a Favourable outcome) / (Total number of outcomes) 

A
Ahmad Shirzai

Hi Rusty,


Probability = Number of favourable Outcomes / Total Number of Outcomes


p (A) = f / N


You need to start by finding the probability of a single outcome. Then find the total number of outcomes that can occur. Finally divide the number of events by the number of possible outcomes.

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Probability of an event = (number of favourable outcomes) / (total number of outcomes)

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M
Muhammad Ramis

Probability of event 'A' is equal to (Number of Event A occurred) divided by (Total Number of Events occurred in Sample Space):


P(A) = n(A)/n(S); where 'A' is Event 'A' Occurred and 'S' is Total Number of Events in Sample Space

Z
Zohair Nayani

Rule for addition- P(AuB)=P(A)+P(B)-P(AnB)

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