What is the value of the expression |x + y| when x = –8 and y =

In a large population, 3% of the people are heroin users. A new drug test correctly identifies users 93% of the time and correct

kari74 [83]

Answer:

(a) The probability tree is shown below.

(b) The probability that a person who does not use heroin in this population tests positive is 0.10.

(c) The probability that a randomly chosen person from this population is a heroin user and tests positive is 0.0279.

(d) The probability that a randomly chosen person from this population tests positive is 0.1249.

(e) The probability that a person is heroin user given that he/she was tested positive is 0.2234.

Step-by-step explanation:

Denote the events as follows:

<em>X</em> = a person is a heroin user

<em>Y</em> = the test is correct.

Given:

P (X) = 0.03

P (Y|X) = 0.93

P (Y|X') = 0.99

(a)

The probability tree is shown below.

(b)

Compute the probability that a person who does not use heroin in this population tests positive as follows:

The event is denoted as (Y' | X').

Consider the tree diagram.

The value of P (Y' | X') is 0.10.

Thus, the probability that a person who does not use heroin in this population tests positive is 0.10.

(c)

Compute the probability that a randomly chosen person from this population is a heroin user and tests positive as follows:

$P(X\cap Y)=P(Y|X)P(X)=0.93\times0.03=0.0279$

Thus, the probability that a randomly chosen person from this population is a heroin user and tests positive is 0.0279.

(d)

Compute the probability that a randomly chosen person from this population tests positive as follows:

P (Positive) = P (Y|X)P(X) + P (Y'|X')P(X')

$=(0.93\times0.03)+(0.10\times0.97)\\=0.1249$

Thus, the probability that a randomly chosen person from this population tests positive is 0.1249.

(e)

Compute the probability that a person is heroin user given that he/she was tested positive as follows:

$P(X|positive)=\frac{P(Y|X)P(X)}{P(positive)} =\frac{0.93\times0.03}{0.1249}= 0.2234$

Thus, the probability that a person is heroin user given that he/she was tested positive is 0.2234.

6 0

3 years ago

I talk to an average of 8 customers per hour during an 8 hour shift and need to increase the amount of customers i help by 20%,

lbvjy [14]

Answer:

The number of customer needed to achieve is 34

Step-by-step explanation:

Given as :

The number of customer per hour = 8

The time taken = 8 hours

The rate of increase = 20 %

Let The increase in number of customer after 20 % increment = x

So , The number of customer after n hours = initial number × $(1+\dfrac{\textrm rate}{100})^{n}$

or, The number of customer after 8 hours = 8 × $(1+\dfrac{\textrm 20}{100})^{8}$

or, The number of customer after 8 hours = 8 × 4.2998

∴The number of customer after 8 hours = 34.39 ≈ 34

Hence The number of customer needed to achieve is 34 answer

8 0

4 years ago

According to the National Weather Service, the average monthly high temperature in the Dallas/Fort Worth, Texas area from the ye

Salsk061 [2.6K]

The average maximum would be C. 76.8 degrees

4 0

3 years ago

A class has 15 boys and 16 girls. What is the probability that a boy's name is drawn at random?

miv72 [106K]

It’s is 15/31 because you have to add 15+16 and you get 31 so since there is 15 boys it would be 15/31

3 0

4 years ago

How do I do this, I don't understand how to set up the problem.

Sedaia [141]

X is 65 because there is a theorem saying that when a transversal crosses two parallel lines, the corresponding angles are congruent. Since x is the other side of the corresponding angle of 115, you have to do 180-115, since a straight line is 180°.

4 0

3 years ago

What is the value of the expression |x + y| when x = –8 and y = –13?