Chance and Probability

Probability tells the degree of uncertainty. It measures the likelihood that an event will occur.

Random Experiment

If the result of the experiment is not known then it is known as a random experiment.

Example

If we throw a dice then the result could be any number from 1 – 6.

Outcomes

When we do an experiment then there could be different results, these possible results of the random experiment are called outcomes.

Example

There are two possible outcomes when we toss a coin i.e. head and tail.

Equally Likely Outcomes

If every outcome has the same possibility of occurring these outcomes are called Equally Likely Outcomes.

Example

If we throw a dice then there is an equal chance of every no. to come while doing the random experiment. i.e. a dice has the same possibility of getting 1, 2, 3, 4, 5 and 6.

Linking Chances to the Probability

\mathrm{Probability=\dfrac{Number\ of\ chances\ for\ a\ particular\ outcome }{Total\ number\ of\ outcomes}}

Example

What is the chance of getting 3 when we throw a dice?

Solution

There is only one chance to get 3 in one throw and the total possible outcomes are 6.

Hence the probability of getting  =\dfrac{1}{6}.

Outcomes as Events

Each outcome or collection of outcomes of an experiment is known as an event.

Example

If we throw a dice then getting each outcome 1, 2, 3, 4, 5 and 6 are events.

Example

What is the event of getting odd numbers when we throw a dice?

Solution

The probability of getting an odd number is 3(odd numbers are 1, 3, 5)

The total number of outcomes is 6. The probability of getting an odd number  =\dfrac{3}{6}.

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