Calculation of probability with arithmetic mean of random variables for a total of 3 times












2














Thanks to @Ben W for his answer to my previous question, now I can calculate and have 3 equal probabilities:



$P(X_1) = P(X_2) = P(X_3) approx 0.000148646896$
with $X_1 = X_2 = X_3 = 1620$



Following up, once that the 4 people got 405 as the arithmetic mean of the number on their cards, then they repeat the drawing 2 more time (3 in total). So, I would like to calculate the probability that the arithmetic mean of the number on their cards is 405 for a total of 3 times.



How to make that?





Some explanation is welcome.










share|cite|improve this question




















  • 1




    "I would like to calculate the probability of the event that 'the above 3 probabilities are the same'" Uh.... I don't understand your question. If you give as a hypothesis that $P(X_1)=P(X_2)=P(X_3)$... then the probability that they are equal is $1$... since you already told us that they are equal. If things are equal then they are equal. A tautology is a tautology...
    – JMoravitz
    Nov 20 '18 at 2:22






  • 1




    I think you misunderstood me. Let me see if I can explain better. Can you describe the physical situation? Are there now twelve players, in three groups of four? What event are you asking to compute the probability of? Etc.
    – Ben W
    Nov 20 '18 at 2:32






  • 1




    You can answer your own question.
    – Ben W
    Nov 20 '18 at 2:48






  • 1




    There is a big difference between asking for the probability that $Pr(X_1=405)=Pr(X_2=405)=Pr(X_3=405)$ and asking for the probability $Pr(X_1=X_2=X_3=405)$.
    – JMoravitz
    Nov 20 '18 at 2:55






  • 2




    Thank you but I don't really keep track nor care about my rep points. I'm in it for the love of the game ; )
    – Ben W
    Nov 20 '18 at 2:58


















2














Thanks to @Ben W for his answer to my previous question, now I can calculate and have 3 equal probabilities:



$P(X_1) = P(X_2) = P(X_3) approx 0.000148646896$
with $X_1 = X_2 = X_3 = 1620$



Following up, once that the 4 people got 405 as the arithmetic mean of the number on their cards, then they repeat the drawing 2 more time (3 in total). So, I would like to calculate the probability that the arithmetic mean of the number on their cards is 405 for a total of 3 times.



How to make that?





Some explanation is welcome.










share|cite|improve this question




















  • 1




    "I would like to calculate the probability of the event that 'the above 3 probabilities are the same'" Uh.... I don't understand your question. If you give as a hypothesis that $P(X_1)=P(X_2)=P(X_3)$... then the probability that they are equal is $1$... since you already told us that they are equal. If things are equal then they are equal. A tautology is a tautology...
    – JMoravitz
    Nov 20 '18 at 2:22






  • 1




    I think you misunderstood me. Let me see if I can explain better. Can you describe the physical situation? Are there now twelve players, in three groups of four? What event are you asking to compute the probability of? Etc.
    – Ben W
    Nov 20 '18 at 2:32






  • 1




    You can answer your own question.
    – Ben W
    Nov 20 '18 at 2:48






  • 1




    There is a big difference between asking for the probability that $Pr(X_1=405)=Pr(X_2=405)=Pr(X_3=405)$ and asking for the probability $Pr(X_1=X_2=X_3=405)$.
    – JMoravitz
    Nov 20 '18 at 2:55






  • 2




    Thank you but I don't really keep track nor care about my rep points. I'm in it for the love of the game ; )
    – Ben W
    Nov 20 '18 at 2:58
















2












2








2







Thanks to @Ben W for his answer to my previous question, now I can calculate and have 3 equal probabilities:



$P(X_1) = P(X_2) = P(X_3) approx 0.000148646896$
with $X_1 = X_2 = X_3 = 1620$



Following up, once that the 4 people got 405 as the arithmetic mean of the number on their cards, then they repeat the drawing 2 more time (3 in total). So, I would like to calculate the probability that the arithmetic mean of the number on their cards is 405 for a total of 3 times.



How to make that?





Some explanation is welcome.










share|cite|improve this question















Thanks to @Ben W for his answer to my previous question, now I can calculate and have 3 equal probabilities:



$P(X_1) = P(X_2) = P(X_3) approx 0.000148646896$
with $X_1 = X_2 = X_3 = 1620$



Following up, once that the 4 people got 405 as the arithmetic mean of the number on their cards, then they repeat the drawing 2 more time (3 in total). So, I would like to calculate the probability that the arithmetic mean of the number on their cards is 405 for a total of 3 times.



How to make that?





Some explanation is welcome.







probability statistics






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 20 '18 at 3:25

























asked Nov 20 '18 at 2:19









Backo

1184




1184








  • 1




    "I would like to calculate the probability of the event that 'the above 3 probabilities are the same'" Uh.... I don't understand your question. If you give as a hypothesis that $P(X_1)=P(X_2)=P(X_3)$... then the probability that they are equal is $1$... since you already told us that they are equal. If things are equal then they are equal. A tautology is a tautology...
    – JMoravitz
    Nov 20 '18 at 2:22






  • 1




    I think you misunderstood me. Let me see if I can explain better. Can you describe the physical situation? Are there now twelve players, in three groups of four? What event are you asking to compute the probability of? Etc.
    – Ben W
    Nov 20 '18 at 2:32






  • 1




    You can answer your own question.
    – Ben W
    Nov 20 '18 at 2:48






  • 1




    There is a big difference between asking for the probability that $Pr(X_1=405)=Pr(X_2=405)=Pr(X_3=405)$ and asking for the probability $Pr(X_1=X_2=X_3=405)$.
    – JMoravitz
    Nov 20 '18 at 2:55






  • 2




    Thank you but I don't really keep track nor care about my rep points. I'm in it for the love of the game ; )
    – Ben W
    Nov 20 '18 at 2:58
















  • 1




    "I would like to calculate the probability of the event that 'the above 3 probabilities are the same'" Uh.... I don't understand your question. If you give as a hypothesis that $P(X_1)=P(X_2)=P(X_3)$... then the probability that they are equal is $1$... since you already told us that they are equal. If things are equal then they are equal. A tautology is a tautology...
    – JMoravitz
    Nov 20 '18 at 2:22






  • 1




    I think you misunderstood me. Let me see if I can explain better. Can you describe the physical situation? Are there now twelve players, in three groups of four? What event are you asking to compute the probability of? Etc.
    – Ben W
    Nov 20 '18 at 2:32






  • 1




    You can answer your own question.
    – Ben W
    Nov 20 '18 at 2:48






  • 1




    There is a big difference between asking for the probability that $Pr(X_1=405)=Pr(X_2=405)=Pr(X_3=405)$ and asking for the probability $Pr(X_1=X_2=X_3=405)$.
    – JMoravitz
    Nov 20 '18 at 2:55






  • 2




    Thank you but I don't really keep track nor care about my rep points. I'm in it for the love of the game ; )
    – Ben W
    Nov 20 '18 at 2:58










1




1




"I would like to calculate the probability of the event that 'the above 3 probabilities are the same'" Uh.... I don't understand your question. If you give as a hypothesis that $P(X_1)=P(X_2)=P(X_3)$... then the probability that they are equal is $1$... since you already told us that they are equal. If things are equal then they are equal. A tautology is a tautology...
– JMoravitz
Nov 20 '18 at 2:22




"I would like to calculate the probability of the event that 'the above 3 probabilities are the same'" Uh.... I don't understand your question. If you give as a hypothesis that $P(X_1)=P(X_2)=P(X_3)$... then the probability that they are equal is $1$... since you already told us that they are equal. If things are equal then they are equal. A tautology is a tautology...
– JMoravitz
Nov 20 '18 at 2:22




1




1




I think you misunderstood me. Let me see if I can explain better. Can you describe the physical situation? Are there now twelve players, in three groups of four? What event are you asking to compute the probability of? Etc.
– Ben W
Nov 20 '18 at 2:32




I think you misunderstood me. Let me see if I can explain better. Can you describe the physical situation? Are there now twelve players, in three groups of four? What event are you asking to compute the probability of? Etc.
– Ben W
Nov 20 '18 at 2:32




1




1




You can answer your own question.
– Ben W
Nov 20 '18 at 2:48




You can answer your own question.
– Ben W
Nov 20 '18 at 2:48




1




1




There is a big difference between asking for the probability that $Pr(X_1=405)=Pr(X_2=405)=Pr(X_3=405)$ and asking for the probability $Pr(X_1=X_2=X_3=405)$.
– JMoravitz
Nov 20 '18 at 2:55




There is a big difference between asking for the probability that $Pr(X_1=405)=Pr(X_2=405)=Pr(X_3=405)$ and asking for the probability $Pr(X_1=X_2=X_3=405)$.
– JMoravitz
Nov 20 '18 at 2:55




2




2




Thank you but I don't really keep track nor care about my rep points. I'm in it for the love of the game ; )
– Ben W
Nov 20 '18 at 2:58






Thank you but I don't really keep track nor care about my rep points. I'm in it for the love of the game ; )
– Ben W
Nov 20 '18 at 2:58












1 Answer
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Just multiply the probabilities together.



You have $0.000148646896^3 ≈ 3.2844869e-12$



Credit @Ben W






share|cite|improve this answer





















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    1 Answer
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    1 Answer
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    active

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    Just multiply the probabilities together.



    You have $0.000148646896^3 ≈ 3.2844869e-12$



    Credit @Ben W






    share|cite|improve this answer


























      0














      Just multiply the probabilities together.



      You have $0.000148646896^3 ≈ 3.2844869e-12$



      Credit @Ben W






      share|cite|improve this answer
























        0












        0








        0






        Just multiply the probabilities together.



        You have $0.000148646896^3 ≈ 3.2844869e-12$



        Credit @Ben W






        share|cite|improve this answer












        Just multiply the probabilities together.



        You have $0.000148646896^3 ≈ 3.2844869e-12$



        Credit @Ben W







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Nov 20 '18 at 2:54









        Backo

        1184




        1184






























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