Maths

>

GCSE

Probability

Question

What is the formula of probability?

2 years ago

·

42 Replies

·

3135 views

R

Rusty Botsford



42 Answers

Ugur Profile Picture
Ugur Verified Sherpa Tutor ✓

MSc. Mathematics Distinction Grade

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.

I'm available for 1:1 private online tuition!

Click here to view my profile and arrange a free introduction.
R
Roshan Sharma

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

D
Dan Bai

z+Y1sPIV1XDAAAAAElFTkSuQmCC



For example, if you roll a six-sided die and want to know the probability of rolling a 3, the formula would be: Since there's only one favourable outcome (rolling a 3) out of six total outcomes. 

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.

Khalid M Profile Picture
Khalid M Verified Sherpa Tutor ✓

Maths professional tutor.

The basic probability formula is P(event A)= (number of favorable outcomes for event A) / (total number of possible outcomes). 

I'm available for 1:1 private online tuition!

Click here to view my profile and arrange a free introduction.
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.

W
Walter Sibanda

Number of favorable outcomes divided by Number of all possible outcomes

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

L
Laura Jones

Probability can be defined as the ratio of the number of favorable outcomes to the total number of outcomes of an event

Think you can help?

More Maths GCSE Questions
Sherpa Badge

Need a GCSE Maths tutor?

Get started with a free online introductions with an experienced and qualified online tutor on Sherpa.

Find a GCSE Maths Tutor