Answer:
D) (0, -3)
Step-by-step explanation:
The solution of two linear equations is the point of intersection of their graphs.
From the graph, the point of intersection of the graphs of the two linear equations is on the y-axis. So, the value on the
axis is always 0. Also, the point is below the x-axis. So, the
value of the point will be negative.
From the choices given, only (0,-3) matches the above conditions.
Therefore, the correct choice is D. (0, -3).
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:
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')
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:
Thus, the probability that a person is heroin user given that he/she was tested positive is 0.2234.