How to calculate the expected value when throwing multiple dices?












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I'm starting to learn probability theory and I found an exercise that states:



On a particular move we throw a 20 sided dice one time, and then we throw a 4 sided dice twice. We substract the sum of the 2 throwings of the 4 sided dice to the value we got throwing the 20 sided dice. So if we throw the first one and we get 18, then we throw to times the 4 sided and we get 1 and 2, the final result will be 15.



How can I calculate the expected value? Should I generate all possible throwing combinations and look for the ones who repeat the most?



How can I calculate which range of results will get on the 50% of the times? (I'm a little bit lost on this one)



Thanks for your attention










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  • 1




    $begingroup$
    You can use E[X-Y-Z]=E[X]-E[Y]-E[Z]
    $endgroup$
    – Michael
    Dec 29 '18 at 13:47
















0












$begingroup$


I'm starting to learn probability theory and I found an exercise that states:



On a particular move we throw a 20 sided dice one time, and then we throw a 4 sided dice twice. We substract the sum of the 2 throwings of the 4 sided dice to the value we got throwing the 20 sided dice. So if we throw the first one and we get 18, then we throw to times the 4 sided and we get 1 and 2, the final result will be 15.



How can I calculate the expected value? Should I generate all possible throwing combinations and look for the ones who repeat the most?



How can I calculate which range of results will get on the 50% of the times? (I'm a little bit lost on this one)



Thanks for your attention










share|cite|improve this question









$endgroup$








  • 1




    $begingroup$
    You can use E[X-Y-Z]=E[X]-E[Y]-E[Z]
    $endgroup$
    – Michael
    Dec 29 '18 at 13:47














0












0








0





$begingroup$


I'm starting to learn probability theory and I found an exercise that states:



On a particular move we throw a 20 sided dice one time, and then we throw a 4 sided dice twice. We substract the sum of the 2 throwings of the 4 sided dice to the value we got throwing the 20 sided dice. So if we throw the first one and we get 18, then we throw to times the 4 sided and we get 1 and 2, the final result will be 15.



How can I calculate the expected value? Should I generate all possible throwing combinations and look for the ones who repeat the most?



How can I calculate which range of results will get on the 50% of the times? (I'm a little bit lost on this one)



Thanks for your attention










share|cite|improve this question









$endgroup$




I'm starting to learn probability theory and I found an exercise that states:



On a particular move we throw a 20 sided dice one time, and then we throw a 4 sided dice twice. We substract the sum of the 2 throwings of the 4 sided dice to the value we got throwing the 20 sided dice. So if we throw the first one and we get 18, then we throw to times the 4 sided and we get 1 and 2, the final result will be 15.



How can I calculate the expected value? Should I generate all possible throwing combinations and look for the ones who repeat the most?



How can I calculate which range of results will get on the 50% of the times? (I'm a little bit lost on this one)



Thanks for your attention







probability probability-theory probability-distributions






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share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Dec 29 '18 at 13:40









Pau MuñozPau Muñoz

154




154








  • 1




    $begingroup$
    You can use E[X-Y-Z]=E[X]-E[Y]-E[Z]
    $endgroup$
    – Michael
    Dec 29 '18 at 13:47














  • 1




    $begingroup$
    You can use E[X-Y-Z]=E[X]-E[Y]-E[Z]
    $endgroup$
    – Michael
    Dec 29 '18 at 13:47








1




1




$begingroup$
You can use E[X-Y-Z]=E[X]-E[Y]-E[Z]
$endgroup$
– Michael
Dec 29 '18 at 13:47




$begingroup$
You can use E[X-Y-Z]=E[X]-E[Y]-E[Z]
$endgroup$
– Michael
Dec 29 '18 at 13:47










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