You toss two coins. This action costs $5$. For each head tossed, you get $2$. If you win (at least one head...












0












$begingroup$


You toss two coins. This action costs $ $ 5$. For each head tossed, you get $$2$. If you win (at least one head tossed) you also get your $$5$ back. What is the expected profit of a round? What should be the sum of the award of winning so that the game is fair (no trend of someone winning or losing)?



At this point I have calculated the possible scenarios:




  • 1/4 - two heads

  • 1/4 - two tails

  • 1/2 - one head, one tail


Hence, you have



$$
left(frac{1}{4} text{chance of winning} ($5+$2+$2- $5)right) times left( frac{1}{2} text{chance of winning} ($5+$2- $5) right) times left( frac{1}{4} text{chance of winning} ($0 - $5) right)$$
-.










share|cite|improve this question











$endgroup$












  • $begingroup$
    You get $2$ what?
    $endgroup$
    – N. F. Taussig
    Jan 23 at 14:22










  • $begingroup$
    Typesetting hint: to display dollar signs, put a backslash in front: $5 gives $5. Otherwise, everything between your dollar signs is interpreted as a mathematical expression.
    $endgroup$
    – Théophile
    Jan 23 at 14:23








  • 1




    $begingroup$
    I think you mean $+$ instead of $*$ in your last sentence. Otherwise, you have exactly written out how to calculate the expected profit of the game. It's unclear what you mean by "the sum of the award of winning" in you second question though.
    $endgroup$
    – kccu
    Jan 23 at 14:33






  • 2




    $begingroup$
    You should have addition signs rather than multiplication signs between each pair of parentheses since the three events are mutually exclusive.
    $endgroup$
    – N. F. Taussig
    Jan 23 at 14:40






  • 1




    $begingroup$
    This is what happens when you don't take the trouble to ensure that your question is reasonably formatted: someone comes along and formats it for you, and while doing so they change a $+$ to $times$ and make it slightly worse (in that respect) than it was before. I recommend you go over the edited post and make sure everything there is exactly how you want it--notably those multiplication signs.
    $endgroup$
    – David K
    Jan 23 at 14:40
















0












$begingroup$


You toss two coins. This action costs $ $ 5$. For each head tossed, you get $$2$. If you win (at least one head tossed) you also get your $$5$ back. What is the expected profit of a round? What should be the sum of the award of winning so that the game is fair (no trend of someone winning or losing)?



At this point I have calculated the possible scenarios:




  • 1/4 - two heads

  • 1/4 - two tails

  • 1/2 - one head, one tail


Hence, you have



$$
left(frac{1}{4} text{chance of winning} ($5+$2+$2- $5)right) times left( frac{1}{2} text{chance of winning} ($5+$2- $5) right) times left( frac{1}{4} text{chance of winning} ($0 - $5) right)$$
-.










share|cite|improve this question











$endgroup$












  • $begingroup$
    You get $2$ what?
    $endgroup$
    – N. F. Taussig
    Jan 23 at 14:22










  • $begingroup$
    Typesetting hint: to display dollar signs, put a backslash in front: $5 gives $5. Otherwise, everything between your dollar signs is interpreted as a mathematical expression.
    $endgroup$
    – Théophile
    Jan 23 at 14:23








  • 1




    $begingroup$
    I think you mean $+$ instead of $*$ in your last sentence. Otherwise, you have exactly written out how to calculate the expected profit of the game. It's unclear what you mean by "the sum of the award of winning" in you second question though.
    $endgroup$
    – kccu
    Jan 23 at 14:33






  • 2




    $begingroup$
    You should have addition signs rather than multiplication signs between each pair of parentheses since the three events are mutually exclusive.
    $endgroup$
    – N. F. Taussig
    Jan 23 at 14:40






  • 1




    $begingroup$
    This is what happens when you don't take the trouble to ensure that your question is reasonably formatted: someone comes along and formats it for you, and while doing so they change a $+$ to $times$ and make it slightly worse (in that respect) than it was before. I recommend you go over the edited post and make sure everything there is exactly how you want it--notably those multiplication signs.
    $endgroup$
    – David K
    Jan 23 at 14:40














0












0








0





$begingroup$


You toss two coins. This action costs $ $ 5$. For each head tossed, you get $$2$. If you win (at least one head tossed) you also get your $$5$ back. What is the expected profit of a round? What should be the sum of the award of winning so that the game is fair (no trend of someone winning or losing)?



At this point I have calculated the possible scenarios:




  • 1/4 - two heads

  • 1/4 - two tails

  • 1/2 - one head, one tail


Hence, you have



$$
left(frac{1}{4} text{chance of winning} ($5+$2+$2- $5)right) times left( frac{1}{2} text{chance of winning} ($5+$2- $5) right) times left( frac{1}{4} text{chance of winning} ($0 - $5) right)$$
-.










share|cite|improve this question











$endgroup$




You toss two coins. This action costs $ $ 5$. For each head tossed, you get $$2$. If you win (at least one head tossed) you also get your $$5$ back. What is the expected profit of a round? What should be the sum of the award of winning so that the game is fair (no trend of someone winning or losing)?



At this point I have calculated the possible scenarios:




  • 1/4 - two heads

  • 1/4 - two tails

  • 1/2 - one head, one tail


Hence, you have



$$
left(frac{1}{4} text{chance of winning} ($5+$2+$2- $5)right) times left( frac{1}{2} text{chance of winning} ($5+$2- $5) right) times left( frac{1}{4} text{chance of winning} ($0 - $5) right)$$
-.







probability statistics






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 23 at 14:38







Radoslav Bonev

















asked Jan 23 at 14:20









Radoslav BonevRadoslav Bonev

414




414












  • $begingroup$
    You get $2$ what?
    $endgroup$
    – N. F. Taussig
    Jan 23 at 14:22










  • $begingroup$
    Typesetting hint: to display dollar signs, put a backslash in front: $5 gives $5. Otherwise, everything between your dollar signs is interpreted as a mathematical expression.
    $endgroup$
    – Théophile
    Jan 23 at 14:23








  • 1




    $begingroup$
    I think you mean $+$ instead of $*$ in your last sentence. Otherwise, you have exactly written out how to calculate the expected profit of the game. It's unclear what you mean by "the sum of the award of winning" in you second question though.
    $endgroup$
    – kccu
    Jan 23 at 14:33






  • 2




    $begingroup$
    You should have addition signs rather than multiplication signs between each pair of parentheses since the three events are mutually exclusive.
    $endgroup$
    – N. F. Taussig
    Jan 23 at 14:40






  • 1




    $begingroup$
    This is what happens when you don't take the trouble to ensure that your question is reasonably formatted: someone comes along and formats it for you, and while doing so they change a $+$ to $times$ and make it slightly worse (in that respect) than it was before. I recommend you go over the edited post and make sure everything there is exactly how you want it--notably those multiplication signs.
    $endgroup$
    – David K
    Jan 23 at 14:40


















  • $begingroup$
    You get $2$ what?
    $endgroup$
    – N. F. Taussig
    Jan 23 at 14:22










  • $begingroup$
    Typesetting hint: to display dollar signs, put a backslash in front: $5 gives $5. Otherwise, everything between your dollar signs is interpreted as a mathematical expression.
    $endgroup$
    – Théophile
    Jan 23 at 14:23








  • 1




    $begingroup$
    I think you mean $+$ instead of $*$ in your last sentence. Otherwise, you have exactly written out how to calculate the expected profit of the game. It's unclear what you mean by "the sum of the award of winning" in you second question though.
    $endgroup$
    – kccu
    Jan 23 at 14:33






  • 2




    $begingroup$
    You should have addition signs rather than multiplication signs between each pair of parentheses since the three events are mutually exclusive.
    $endgroup$
    – N. F. Taussig
    Jan 23 at 14:40






  • 1




    $begingroup$
    This is what happens when you don't take the trouble to ensure that your question is reasonably formatted: someone comes along and formats it for you, and while doing so they change a $+$ to $times$ and make it slightly worse (in that respect) than it was before. I recommend you go over the edited post and make sure everything there is exactly how you want it--notably those multiplication signs.
    $endgroup$
    – David K
    Jan 23 at 14:40
















$begingroup$
You get $2$ what?
$endgroup$
– N. F. Taussig
Jan 23 at 14:22




$begingroup$
You get $2$ what?
$endgroup$
– N. F. Taussig
Jan 23 at 14:22












$begingroup$
Typesetting hint: to display dollar signs, put a backslash in front: $5 gives $5. Otherwise, everything between your dollar signs is interpreted as a mathematical expression.
$endgroup$
– Théophile
Jan 23 at 14:23






$begingroup$
Typesetting hint: to display dollar signs, put a backslash in front: $5 gives $5. Otherwise, everything between your dollar signs is interpreted as a mathematical expression.
$endgroup$
– Théophile
Jan 23 at 14:23






1




1




$begingroup$
I think you mean $+$ instead of $*$ in your last sentence. Otherwise, you have exactly written out how to calculate the expected profit of the game. It's unclear what you mean by "the sum of the award of winning" in you second question though.
$endgroup$
– kccu
Jan 23 at 14:33




$begingroup$
I think you mean $+$ instead of $*$ in your last sentence. Otherwise, you have exactly written out how to calculate the expected profit of the game. It's unclear what you mean by "the sum of the award of winning" in you second question though.
$endgroup$
– kccu
Jan 23 at 14:33




2




2




$begingroup$
You should have addition signs rather than multiplication signs between each pair of parentheses since the three events are mutually exclusive.
$endgroup$
– N. F. Taussig
Jan 23 at 14:40




$begingroup$
You should have addition signs rather than multiplication signs between each pair of parentheses since the three events are mutually exclusive.
$endgroup$
– N. F. Taussig
Jan 23 at 14:40




1




1




$begingroup$
This is what happens when you don't take the trouble to ensure that your question is reasonably formatted: someone comes along and formats it for you, and while doing so they change a $+$ to $times$ and make it slightly worse (in that respect) than it was before. I recommend you go over the edited post and make sure everything there is exactly how you want it--notably those multiplication signs.
$endgroup$
– David K
Jan 23 at 14:40




$begingroup$
This is what happens when you don't take the trouble to ensure that your question is reasonably formatted: someone comes along and formats it for you, and while doing so they change a $+$ to $times$ and make it slightly worse (in that respect) than it was before. I recommend you go over the edited post and make sure everything there is exactly how you want it--notably those multiplication signs.
$endgroup$
– David K
Jan 23 at 14:40










2 Answers
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$begingroup$

Your computation of the expected return is correct. Probably the sum to award question means to replace $2$ with some number to make the expected return $0$. Just replace $2$ by $x$ in your expected return expression, set it to zero, and solve the resulting equation.






share|cite|improve this answer









$endgroup$





















    0












    $begingroup$

    You are almost right. But recalling the expectation definition : $E(X) = sum p(X) X$ you should rather write



    $$ frac{1}{4} times ($5+$2+$2- $5) + frac{1}{2} times ($5+$2- $5) + frac{1}{4}times ($0 - $5) $$






    share|cite|improve this answer









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      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      0












      $begingroup$

      Your computation of the expected return is correct. Probably the sum to award question means to replace $2$ with some number to make the expected return $0$. Just replace $2$ by $x$ in your expected return expression, set it to zero, and solve the resulting equation.






      share|cite|improve this answer









      $endgroup$


















        0












        $begingroup$

        Your computation of the expected return is correct. Probably the sum to award question means to replace $2$ with some number to make the expected return $0$. Just replace $2$ by $x$ in your expected return expression, set it to zero, and solve the resulting equation.






        share|cite|improve this answer









        $endgroup$
















          0












          0








          0





          $begingroup$

          Your computation of the expected return is correct. Probably the sum to award question means to replace $2$ with some number to make the expected return $0$. Just replace $2$ by $x$ in your expected return expression, set it to zero, and solve the resulting equation.






          share|cite|improve this answer









          $endgroup$



          Your computation of the expected return is correct. Probably the sum to award question means to replace $2$ with some number to make the expected return $0$. Just replace $2$ by $x$ in your expected return expression, set it to zero, and solve the resulting equation.







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Jan 23 at 14:41









          Ross MillikanRoss Millikan

          299k24200374




          299k24200374























              0












              $begingroup$

              You are almost right. But recalling the expectation definition : $E(X) = sum p(X) X$ you should rather write



              $$ frac{1}{4} times ($5+$2+$2- $5) + frac{1}{2} times ($5+$2- $5) + frac{1}{4}times ($0 - $5) $$






              share|cite|improve this answer









              $endgroup$


















                0












                $begingroup$

                You are almost right. But recalling the expectation definition : $E(X) = sum p(X) X$ you should rather write



                $$ frac{1}{4} times ($5+$2+$2- $5) + frac{1}{2} times ($5+$2- $5) + frac{1}{4}times ($0 - $5) $$






                share|cite|improve this answer









                $endgroup$
















                  0












                  0








                  0





                  $begingroup$

                  You are almost right. But recalling the expectation definition : $E(X) = sum p(X) X$ you should rather write



                  $$ frac{1}{4} times ($5+$2+$2- $5) + frac{1}{2} times ($5+$2- $5) + frac{1}{4}times ($0 - $5) $$






                  share|cite|improve this answer









                  $endgroup$



                  You are almost right. But recalling the expectation definition : $E(X) = sum p(X) X$ you should rather write



                  $$ frac{1}{4} times ($5+$2+$2- $5) + frac{1}{2} times ($5+$2- $5) + frac{1}{4}times ($0 - $5) $$







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered Jan 23 at 14:42









                  leonbloyleonbloy

                  41.5k647108




                  41.5k647108






























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