The newest invention of the 6.431x staff is a three-sided die. On any roll of this die, the result is 1 with probability 1/2, 2 with probability 1/4, and 3 with probability 1/4. Consider a sequence of six independent rolls of this die. Find the probability that exactly two of the rolls result in a 3.

Respuesta :

Answer:

The answer is 0.23(approx).

Step-by-step explanation:

The given die is a three sided die, hence, there are only three possibilities of getting the outcomes.

We need to find the probability of getting exactly 3s as the result.

From the sequence of 6 independent rolls, 2 rolls can be chosen in [tex]^6C_2 = \frac{6!}{2!\times4!} = \frac{30}{2} = 15[/tex] ways.

The probability of getting two 3 as outcome is [tex]\frac{1}{4} \times\frac{1}{4} = \frac{1}{16}[/tex].

In the rest of the 4 sequences, will not be any 3 as outcome.

Probability of not getting a outcome rather than 3 is [tex]1 - \frac{1}{4} = \frac{3}{4}[/tex].

Hence, the required probability is [tex]15\times\frac{1}{16}(\frac{3}{4})^4 = \frac{1215}{4096}[/tex]≅0.2966 or, 0.23.

Binomial distribution has only two possible outcomes. The probability that exactly two of the 6 rolls result in a 3 is 0.131835.

What is Binomial distribution?

A common discrete distribution is used in statistics, as opposed to a continuous distribution is called a Binomial distribution. It is given by the formula,

[tex]P(x) = ^nC_x p^xq^{(n-x)}[/tex]

Where,

x is the number of successes needed,

n is the number of trials or sample size,

p is the probability of a single success, and

q is the probability of a single failure.

We know that the probability of coming a three when the dice is rolled is 1/4(0.25), also, given that the probability of not being coming three, therefore, the probability of the outcome being one and two is 1/2 and 1/4 respectively. therefore,

The probability of three as an outcome is 0.25,

The probability of three not coming as an outcome is  [tex]\dfrac{1}{2} +\dfrac{1}{4} = \dfrac{3}{4}=0.75[/tex].

As we can see that there are only two outcomes possible, either 3 will come or three will not come, therefore, we can apply binomial distribution here, where

The probability of 3 as result, p = 0.25

The probability of three is not the result, q = 0.75

Substituting the values in the formula of the binomial distribution for 2 success,

[tex]\begin{aligned}P(X=2) &= ^6C_3 (0.25)^3 (0.75)^{(6-3)}\\& = 20 \times 0.015625 \times 0.421875\\& = 0.131835 \end{aligned}[/tex]

Hence,  the probability that exactly two of the 6 rolls result in a 3 is 0.131835.

Learn more about Binomial Distribution:

https://brainly.com/question/12734585