Consider the following strategy playing the roulette. Bet $1 on red. If red appears (which happens with probability 18/38), then take $1 and stop playing for the day. If red does not appear, then bet additional $1 on red each of the following two rounds, and then stop playing for the day no matter the outcome. Let X be the net gain (a negative gain means a loss). (a) Find the probability mass function of X; (b) Compute P.X > 0/: Is this a good strategy

Respuesta :

Answer:

a.[tex]\int(x_i)=p(X=x_i)[/tex]

b.[tex]P(X>0)=0.5918[/tex]

C.No

Explanation:

Let X be the probability of a net gain.

a.Given that [tex]X[/tex] is a discrete random variable,[tex]\int(x_i)[/tex] is its probability mass function defined as:

[tex]\int(x_i)=p(X=x_i)[/tex]    #for all [tex]i[/tex].

b. Possible outcomes of X are [tex]1,-1,-3[/tex]. A win of $1 occurs when the gambler wins/loses the first bet but is successful in the next two. A win of -$1 occurs in the, if the gambler loses the first and second but wins [tex]3^r^d[/tex] or loses first and third but wins [tex]2^n^d[/tex]. The gambler wins -$3 if he loses all three bets.

[tex]P(X>0)=P(X=1)=\frac{18}{38}+\frac{20}{38}(\frac{18}{38})^2=\frac{4059}{6859}\\=0.5918[/tex]

c.No. The gambler has a more than 50% probability of winning. The winnings are however high risk and less than [tex]zero.[/tex]