In an article that appears on a website,† Carlton Gunn, a public defender in Seattle, Washington, wrote about how he uses statistics in his work as an attorney. He states the following. I personally have used statistics in trying to challenge the reliability of drug testing results. Suppose the chance of a mistake in the taking and processing of a urine sample f

A First Course in Probability (10th Edition)
10th Edition
ISBN:9780134753119
Author:Sheldon Ross
Publisher:Sheldon Ross
Chapter1: Combinatorial Analysis
Section: Chapter Questions
Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...
icon
Related questions
Topic Video
Question
In an article that appears on a website,† Carlton Gunn, a public defender in Seattle, Washington, wrote about how he uses statistics in his work as an attorney. He states the following.
I personally have used statistics in trying to challenge the reliability of drug testing results. Suppose the chance of a mistake in the taking and processing of a urine sample for a drug test is just 1 in 100. And your client has a "dirty" (i.e., positive) test result. Only a 1 in 100 chance that it could be wrong? Not necessarily. If the vast majority of all tests given—say 99 in 100—are truly clean, then you get one false dirty and one true dirty in every 100 tests, so that half of the dirty tests are false.
Define the following events as given below.
  • TD = event that the test result is dirty
  • TC = event that the test result is clean
  • D = event that the person tested is actually dirty
  • C = event that the person tested is actually clean
(a)
Using the information in the quote, compute the following values.
(i)
P(TD|D)
 
(ii)
P(TD|C)
 
(iii)
P(C)
 
(iv)
P(D)
 
(b)
Use the probabilities from part (a) to construct a hypothetical 1,000 table. (Round your answers to the nearest integer.)
  TD TC Total
D      
C      
Total     1,000
(c)
What is the value of 
P(TD)
 based on the table values?
 
(d)
Use the information in the table to calculate the probability that a person is clean given that the test result is dirty, 
P(C|TD).
 
Is this value consistent with the argument given in the quote? Explain.
Yes, this value is consistent with the argument given in the quote, namely, half of the dirty tests are false.No, this value is not consistent with the argument given in the quote, namely, half of the dirty tests are false.    
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 5 steps with 3 images

Blurred answer
Knowledge Booster
Hypothesis Tests and Confidence Intervals for Proportions
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, probability and related others by exploring similar questions and additional content below.
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
A First Course in Probability (10th Edition)
A First Course in Probability (10th Edition)
Probability
ISBN:
9780134753119
Author:
Sheldon Ross
Publisher:
PEARSON
A First Course in Probability
A First Course in Probability
Probability
ISBN:
9780321794772
Author:
Sheldon Ross
Publisher:
PEARSON