Probability doubt - where am i wrong?

In summary, the conversation discusses the concept of probability in relation to a dice where the probability of obtaining a number is proportional to the number itself. The speaker also mentions the normal method of finding probabilities in a regular dice and how it cannot be applied in this case. They also pose a question about why the formula for calculating probabilities cannot be used in this scenario. The reply suggests that the formula only works when each case is equally likely. Finally, the conversation briefly mentions the drawbacks of the "Classical" definition of probability.
  • #1
jd12345
256
2
There is a dice where probability of obtaining a number is proportional to the number itself.
I have done these problems and the probabilties are 1/21, 2/21,/3/21,/4/21,/5/21 and 6/21

In a normal dice when you have to find probabilities of say, 2 and 4 we do it by favourable cases / total number of cases = 2/6 = 1/3

But you can't apply that method in this case - i know that but why?

Probability of 2 or 4 in this case would be 2/21 + 4/21 = 6/21
but why can't we do this by favourable cases / total number of cases?
 
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  • #2
hi jd12345! :smile:
jd12345 said:
… but why can't we do this by favourable cases / total number of cases?

that formula only applies when each case is equally likely :wink:
 
  • #3
Check the three drawbacks of "Classical" definition.
 

1. What is probability doubt?

Probability doubt refers to a situation where an individual is uncertain about the likelihood or chance of a certain event occuring. It is a common occurrence in statistics and decision making, where the outcome of a situation is not completely known.

2. How do you calculate probability?

Probability is calculated by dividing the number of favorable outcomes by the total number of possible outcomes. This is known as the classical definition of probability. Other methods of calculating probability include empirical probability and subjective probability.

3. What factors can influence probability doubt?

There are several factors that can influence probability doubt, such as the amount of information available, the complexity of the situation, and personal biases or beliefs. Additionally, the presence of random or unpredictable events can also contribute to probability doubt.

4. How can probability doubt be reduced?

Probability doubt can be reduced by gathering more information about the situation, using statistical tools and techniques, and considering the potential biases or uncertainties in the data. It is also helpful to consult with other experts or professionals in the field to gain different perspectives.

5. What are some common mistakes people make when dealing with probability doubt?

Some common mistakes people make when dealing with probability doubt include relying solely on intuition or gut feelings, neglecting to consider all possible outcomes, and not accounting for biases or limitations in the data. It is important to approach probability doubt objectively and carefully consider all relevant factors.

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