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   | Probability |

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Many of the events occurring in daily life cannot be accurately predicted for various reasons. Most of these facts are influenced by external factors. There are also phenomena which are directly influenced by random, which means that we are unsure about what will happen. However, the probability allows us to be closer to these events and study them, by settingthe possibilities of its occurrence and by providing methods for its calculation.
Some of these methods of probability lead us to discover that some events are more or less likely to occur. Our senses, prior information that we have, our beliefs or positions, our inclinations, are some of the factors that do not allow us to make systematic weightings. Probability allows us to study events ina systematic way and closer to reality, giving us accurate, reliable, and useful information for decision-making.
Which is the definition of probability in the dictionary?
 A measure of how likely it is that some event will occur. |
The probability offers us a systematic study which allows us to increase the degree of confidence that we can in the moment of taking a decision withoutthe certainty that all assumptions will occur
Explain with an example the following concepts:
Deterministic phenomenon or experiment:When we throw a glass to the floor, you know that it is going to break into pieces. A deterministic phenomenon is the one in which we are completely sure of the result.    |
Random phenomenon or experiment:  When we throw a dice, we don´t know whichnumber is going to be in the top when it falls.A random phenomenon is the one in which we cannot know the result.  |
How do we call the set consisting of all the possible results of a random experiment?
 Sample space.   |
For example, if a dice is thrown and we look at the upper face, the sample space is:
E = {1, 2, 3, 4, 5, 6}
Each of the possible results of a random experimentis called event.
The probability, P(A), is a fractional number between zero and one, which can also be represented as a percentage between 0% and 100%.
The probability is objective when it is obtained from numeric calculations. While the subjective probability only reflects the perception of the person who is emitting it.
The probabilistic focus of objective implies that all theresults of the experiment are the same likely to happen, and then the probability calculation is:
Probability of A = P (A) = n(A)n(E) , where:
n(A) means the number of possible results of event A.
n(E) means the total number of possible events or the sample space.
For example, in the case of the dice, determine the probability of obtaining a number less than three.
Then the set ofsuccessful results is:
A = {1, 2} where n(A) = 2 and n (E) = 6
By therefore:
P(A) = 2/6
Which can be simplified to:
P(A) = 1/3
The focus of the classic probability (which base is formed by a prior statistic) of the objective probability is calculated by dividing the number of favorable events obtained, between the total.
Take a look at the frequency distribution tableof your statistical work "hours online" and determine the probability of choosing, at random, a student who spends in average three hours on the Internet.
According to the frequency distribution table:
n(A)= 1
n(E) = 161
Then P(A) = 1/161
Types of events.
If two or more events do not occur simultaneously, they are called mutually exclusive events, which means that the...
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