Twelve jurors are randomly selected from a population of 4 million residents. Of these 4 million​ residents, it is known that 46​% are of a minority race. Of the 12 jurors​ selected, 2 are minorities.
​(a) What proportion of the jury described is from a minority​ race? ​
(b) If 12 jurors are randomly selected from a population where 46​% are​ minorities, what is the probability that 2 or fewer jurors will be​ minorities? ​
(c) What might the lawyer of a defendant from this minority race​ argue?

Respuesta :

Answer:  a) 0.17, b) 0.0363

Step-by-step explanation:

Since we have given that

Number of jurors selected = 12

Number of minorities of jurors = 2

​(a) What proportion of the jury described is from a minority​ race? ​

[tex]\dfrac{2}{12}=\dfrac{1}{6}=0.166666\approx0.17[/tex]

(b) If 12 jurors are randomly selected from a population where 46​% are​ minorities, what is the probability that 2 or fewer jurors will be​ minorities?

Let X be the number of jurors who are minorities.

Probability of getting minorities = 0.46

Probability of getting no minorities = 1-0.46 =0.54

[tex]P(X\leq 2)=^{12}C_0(0.54)^{12}+^{12}C_1(0.46)(0.54)^{11}+^{12}C_2(0.46)^2(0.54)^{10}\\\\P(X\leq 2)=0.0363[/tex]

(c) What might the lawyer of a defendant from this minority race​ argue?

Since the number of minorities juror are high among the population.

Hence, a) 0.17, b) 0.0363

Using the binomial distribution, it is found that:

a) 0.1667 = 16.67% of the jury described is from a minority​ race.

b) 0.0363 = 3.63% probability that 2 or fewer jurors will be​ minorities.

c) There is a low probability of a jury with 2 or fewer jurors as minorities, thus, the lawyer could argue that the lack of minorities in the jury was done on purpose to harm his client.

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For each juror, there are only two possible outcomes. Either it is a minority, or it is not. The probability of a juror being a minority is independent of any other juror, which means that the binomial distribution is used to solve this question.

Binomial probability distribution  

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]  

The parameters are:

  • x, which is the number of successes.
  • n, which is the number of trials.
  • p, which is the probability of a success on a single trial.

In this problem:

  • 12 jurors, thus [tex]n = 12[/tex].
  • 46% minorities, thus [tex]p = 0.46[/tex].

Item a:

2 out of 12 are minorities, thus:

[tex]p = \frac{2}{12} = \frac{1}{6} = 0.1667[/tex]

0.1667 = 16.67% of the jury described is from a minority​ race.

Item b:

This is:

[tex]P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2)[/tex]

In which

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 0) = C_{12,0}.(0.46)^{0}.(0.54)^{12} = 0.0006[/tex]

[tex]P(X = 1) = C_{12,1}.(0.46)^{1}.(0.54)^{11} = 0.0063[/tex]

[tex]P(X = 2) = C_{12,2}.(0.46)^{2}.(0.54)^{10} = 0.0294[/tex]

Then

[tex]P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2) = 0.0006 + 0.0063 + 0.0294 = 0.0363[/tex]

0.0363 = 3.63% probability that 2 or fewer jurors will be​ minorities.

Item c:

There is a low probability of a jury with 2 or fewer jurors as minorities, thus, the lawyer could argue that the lack of minorities on the jury was done on purpose to harm his client.

A similar problem is given at https://brainly.com/question/13965196