The everyday definition of the term "probability" is the chance that a particular event will occur.
For example:
What is the probability that when we roll a die we will get the number. 2?
What is the probability that when tossing a coin we get "heads"?
So, as can be understood, probability is the numerical expression for the occurrence of a particular event:
Consider the following example:
When tossing a die, the possible outcomes are any of the numbers between. 1 and6.
Any outcome between 1 and 6 is a possible event.
The outcome 7, for example, is not possible, so 7 is an impossible event.
The probability is calculated as follows:
If we go back to our previous example and throw the dice, what is the probability that we will get the result2?
The number of possibilities of the searched case 1 (because there is only one outcome that is possible for us)
Total options: 6 (the total possible outcomes are from 1 to 6)
Therefore, the probability of rolling a die to get the outcome 2 is ⅙.
And now let us consider what is our probability of obtaining an outcome between1 and3 on a single roll of the dice?
The number of possibilities of the searched case 3 (each of the outcomes 1,2,3 meets our requirement)
Total options: 6 (the total possible outcomes are from 1 to 6)
Therefore, the chance of rolling a single die to get an outcome between 1 and 3 is 63, each of them is a "possible event".
In the same way, we can check what is the probability that we get the result7?
The number of possibilities of the requested case 0.
Therefore, the chance of rolling our die to get the result 7 is 0; this is an "impossible event".
What is the probability that we get a result between1 and6?
The number of possibilities of the requested case 6 (1,2,3,4,5,6 All possible outcomes in fact)
Total options: 6 (total possible outcomes are from 1 to 6)
Therefore, the probability of dropping a single die to obtain an outcome between 1 and 6 is 6/6, i.e. 1. This outcome is a "certain event". As can be seen, the probability will always be between 0 and 1, where probability 0 is an impossible event, probability 1 is a certain event and everything in between is a possible event.
We will look at probability on the numerical axis:
Probability allows us to calculate different possibilities and situations. For example:
Frequency: the number of times we obtain a certain outcome.
Common: the result obtained more times
Relative frequency: the number of times a certain result was obtained out of the total number of results:
For example:
We rolled the dice ten times and obtained the following results:
1,2,2,5,5,5,4,3,6,3
What is the frequency of the result3?
We obtained the result 3 twice so the frequency is 2.
What is the common result in our experiment?
5 is the result obtained the most number of times and therefore the most common is 5.
What is the relative frequency of the result3?
We obtained the outcome 3 twice out of the ten times we rolled the die. Thus, the relative frequency of the outcome 3 is 102 (or ⅕ ).
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