Definition of Probability


 
 
Concept Explanation
 

Definition of Probability

Definition of Probability: 

Probability is considered as a branch of mathematics that deals with uncertainty. It has been developed out of practical considerations and is used in taking decisions in almost every field. For example, while going out of house on cloudy day we have to take decision whether we should carry an umbrella or not. Such type of decision is taken by taking into consideration the probability of the occurrence of the event.

Let n be the total number of trials and m  be the total number of trials in which the event has happened. The empirical probability P(E) of an event to occur is defined as:

P(E)=frac{Number ;of ;trials; in; which; the; event; happened}{The; total; number; of; trials}=frac{m}{n}

0leq mleq n;;Rightarrow 0leq frac{m}{n}leq 1;;Rightarrow 0 leq P(E)leq 1

As the number of favourable trials will always be less than the total trials, so the probability of an event to occur will always be less than 1.

Illustration: An experiment was done 250 times in a day. 150 outcomes from the experiment were favourable, The probability that the next outcome is favourable will be ______________.

A. 1                     B. Less than 1                  C. More than 1             D. Zero

Answer : B

Solution: Total number of trials = 250

No of favourable trials= 150

dpi{110} P(E)=frac{Number ;of ;trials; in; which; the; event; happened}{The; total; number; of; trials}=frac{150}{250}=frac{3}{5}

The probability will be less that 1

Sample Questions
(More Questions for each concept available in Login)
Question : 1

21 boys and 23 girls participate in a painting competition. The probability that a girl wins the competition will be _____________.

Right Option : C
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Explanation
Question : 2

When the probability of an event is 0, then the event is known as _________________

Right Option : D
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Explanation
Question : 3

An experiment was done 300 times in a day. 100 outcomes from the experiment were unfavourable, the probability that the next outcome is unfavourable will be ______________.

Right Option : D
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Explanation
 
 
 
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