A fair die is rolled 10 times. Find the expected value of:a) the sum of the numbers in the ten rolls;b) the number of multiples of three in the ten rolls;c) the number of different faces that appear in the ten rolls. (Hint:Use the indicator method.LetAibe the event that theith face appears at least once.)

Respuesta :

Answer:

a) 3.5

b) 3.33

c) [tex]6 - 6\left(\begin{array}{ccc}5\\6\end{array}\right)^{10}[/tex]

Step-by-step explanation:

As given,

A fair die is rolled 10 times

a)

Expected value of Sum of the number in 10 rolls = [tex]\frac{1}{6}(1+2+3+4+5+6) = \frac{21}{6}[/tex]

                                                                                = 3.5

∴ we get

Expected value of Sum of the number in 10 rolls = 3.5

b)

Ley Y : number of multiples of 3

Y be Binomial

Y - B(n = 10, p = [tex]\frac{2}{6}[/tex] )

Now,

Expected value = E(Y) = np = 10×[tex]\frac{2}{6}[/tex]  = 3.33

c)

Let m = total number of faces in a die

⇒m = 6

As die is roll 10 times

⇒n = 10

Now,

Let Y = number of different faces appears

Now,

Expected value, E(Y) = m - m[tex]\left(\begin{array}{ccc}m-1\\m\end{array}\right)^{n}[/tex]

                                  = [tex]6 - 6\left(\begin{array}{ccc}6-1\\6\end{array}\right)^{10} = 6 - 6\left(\begin{array}{ccc}5\\6\end{array}\right)^{10}[/tex]

In this exercise we have to use probability knowledge to calculate the times the numbers of a roll, in this way we have to:

a) [tex]3.5[/tex]

b) [tex]3.33[/tex]

c) [tex]6-6\left[\begin{array}{cc}5\\6\2\end{array}\right] ^{10}[/tex]

Given that a fair die is rolled 10 times:  

a) Expected value of Sum of the number in 10 rolls  :

[tex]\frac{1}{6} (1+2+3+4+5+6)= \frac{21}{6} = 3.5[/tex]                                                                            

b) Using the formula of the binomial that is represented by:

[tex]Y - B(n = 10, p = \frac{2}{6})[/tex]

Expected value:  [tex]E(Y) = np = (10)(\frac{2}{6} ) = 3.33[/tex]

c) Looking at the 10 times the roll does, we have that it will be. Let m = total number of faces in a die   that represents m  = 6, as die is roll 10 times that represents n = 10. Now,  Expected value:

[tex]= E(Y) = m - m \left[\begin{array}{cc}m-1\\m\\ \end{array}\right] \\= 6-6\left[\begin{array}{cc}5\\6\2\end{array}\right] ^{10}[/tex]

See more about probability at brainly.com/question/795909