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How do you find the probability of something?

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blahxx123 | Student, Grade 10 | (Level 1) eNoter

Posted July 30, 2010 at 8:56 PM via web

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How do you find the probability of something?

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neela | High School Teacher | (Level 3) Valedictorian

Posted July 30, 2010 at 9:25 PM (Answer #1)

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Probabale event is a situation where event may happen or not. Probability  is always expressed in a measure from 0 to 1. For an event which cannot happen, the probability 0. For an event which certainly happens, the probaility is 1. We may also say probality in percentage also. The calculation and definition of probility is:

If there are n exhaustive and mutuallyexclusive and equally likelycases and m of them are favourable to an event A, the probability of the happening of  A is defined as a ratiom/n.

Example: A bag contains 3 green and 2 red balls. What is the probability that a randomly drawn ball is Black .  Answer is zero ,as there are no black balls. If it is to be green the probility of getting it is 3/5.

Hope this may help.

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hala718 | High School Teacher | (Level 1) Educator Emeritus

Posted July 31, 2010 at 12:09 AM (Answer #2)

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The probability is the chance that certain event may occur or not occur.

To calculate the probability you need to figure out the possible outcomes and then determine the event's outcomes.

For example:  in a regular die we need to find the probability of getting a (2)

First we need to determine what possible outcomes could occur from rolling the die which is: 1, 2, 3, 4, 5, or, 6

The total number of outcomes is 6.

Then the chance or the probability of getting a two is one to six , 1:6   or 1/6.

If we need the probability of getting an even number, first we determine the outcomes which is: 2, 4, 6

Then the chances for the even number to occur is 3 to 6 or 3:6

Then the probability = 3/6 = 1/2

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