Stochastic: Difference between revisions

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(Created page with "{{a|design|}}{{d|Stochastic|/stəˈkæstɪk/|adj|}} Of an event, to have a random probability distribution or pattern to which one may assign a probability but not predic...")
 
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{{a|design|}}{{d|Stochastic|/stəˈkæstɪk/|adj|}}
{{a|design|}}{{d|Stochastic|/stəˈkæstɪk/|adj|}}


Of an event, to have a random [[probability]] distribution or pattern to which one may assign a probability but not predict precisely. To be compared with [[deterministic]] (where one can predict the event precisely) and [[uncertain]] where one cannot even assign a probability.
Of an event, to have a random distribution or pattern to which one may assign a [[probability]] but may not predict precisely. To be compared with [[deterministic]] (where one can predict the event precisely) and [[uncertain]] where one cannot even assign a probability.


The outcome of rolling dice is stochastic: you know there are 36 possible outcomes, each of them is equally likely (1/36), but it is impossible to determine which will happen next time you roll the dice. Nonetheless you know the probability of a given outcome is 0.02777 recurring.  
The outcome of rolling dice is stochastic: there are 36 possible outcomes, each of them is equally likely (1/36), but it is impossible to determine which will happen next time you roll the dice. Nonetheless, you know the probability of a given outcome is 0.02777 recurring.  


The price of a stock market index at close tomorrow is ''sort of'' stochastic, in that it must be a number and that number must  be between zero and the total value of all issued currency in the world, but beyond that it is not possible to accurately assign a probability, as [[Standard deviation|David “25-Sigma-Several Days-In-A-Row” Viniar]] would — probably? — tell you.
The price of a stock market index at a point in the future is ''sort of'' stochastic, in that it must be a number and that number must  be between zero and the total value of all issued currency in the world, but beyond that it is not possible to accurately assign a [[probability]], as [[Standard deviation|David “25-Sigma-Several Days-In-A-Row” Viniar]] would — probably? — tell you. So it isn’t really stochastic. To qualify as a random distribution, events must be independent, each value must have a non-negative value, and the value of all events must add to 1. There must be a finite possible number of events.
 
What Elon Musk is going to say on [[Twitter]] tomorrow is ''uncertain''. There is no way of predicting it, or even assigning a probability to it. It is ''not even random''.