Question

Assume that 0.4% of the population has a condition that is not detectible by simple external...

Assume that 0.4% of the population has a condition that is not detectible by simple external observation. A diagnostic test is available for this condition, but, like most tests, it is not perfect. The test correctly diagnoses, with a positive result, those with the condition 99.7% of the time. The test correctly identifies, with a negative result, those without the condition 98.5% of the time.

  1. Let the event C1 represent the presence of the condition and C2 represent the absence of the condition, and let event T represent a positive test result (meaning the test indicated, either correctly or incorrectly, that a person has the condition) and TC represent a negative test result (meaning the test indicated, either correctly or incorrectly, that a person does not have the condition). List symbolically the information given in the introductory statement at the top of the page.

                            

  1. If a randomly selected member of the population tests positive for the condition, what is the probability that the person has the condition? (Report or round your answer to 3 decimal places.)

                      Find:

                      Formula(s):

                      Computations:

                      Answer:

  1. If a randomly selected member of the population tests positive for the condition, what is the probability that the person does not have the condition?
  1. If a randomly selected member of the population tests negative for the condition, what is the probability that the person has the condition? (Report or round your answer to 6 decimal places.)

    Assume that 0.4% of the population has a condition that is not detectible by simple external observation. A diagnostic test is available for this condition, but, like most tests, it is not perfect. The test correctly diagnoses, with a positive result, those with the condition 99.7% of the time. The test correctly identifies, with a negative result, those without the condition 98.5% of the time.

  2. Let the event C1 represent the presence of the condition and C2 represent the absence of the condition, and let event T represent a positive test result (meaning the test indicated, either correctly or incorrectly, that a person has the condition) and TC represent a negative test result (meaning the test indicated, either correctly or incorrectly, that a person does not have the condition). List symbolically the information given in the introductory statement at the top of the page.
  3.                             

  4. If a randomly selected member of the population tests positive for the condition, what is the probability that the person has the condition? (Report or round your answer to 3 decimal places.)
  5.                       Find:

                          Formula(s):

                          Computations:

                          Answer:

  6. If a randomly selected member of the population tests positive for the condition, what is the probability that the person does not have the condition?
  7. If a randomly selected member of the population tests negative for the condition, what is the probability that the person has the condition? (Report or round your answer to 6 decimal places.)

Homework Answers

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
3. A diagnostic test has 95% sensitivity (the probability a person with the condition tests positive...
3. A diagnostic test has 95% sensitivity (the probability a person with the condition tests positive = 0.95) and 95% specificity (the probability a person without the condition tests negative = 0.95). In a population of people given the test, 1% of the people have the condition (probability a person has the condition = 0.01). (a) What proportion of the people will test positive? (b) Given a person has tested positive, what is the probability he/she has the condition?
Two percent of the population has a certain condition for which there are two diagnostic tests....
Two percent of the population has a certain condition for which there are two diagnostic tests. Test A, which costs $1 per person, gives positive results for 80% of persons with the condition and for 5% of the persons without the condition. Test B, which costs $100 per person, gives positive results for all persons with the condition and negative results for all persons without it. (a) Suppose that Test B is given to 150 persons, at a cost of...
A certain genetic condition affects 5% of the population in a city of 10,000. Suppose there...
A certain genetic condition affects 5% of the population in a city of 10,000. Suppose there is a test for the condition that has an error rate of 1% (i.e., 1% false negatives and 1% false positives). Consider the values that would complete the table below.       Has condition       Does not have condition       Totals Test positive Test negative Totals What is the probability (as a percentage) that a person does not have the condition if he or she...
The most commonly used test for HIV has a sensitivity of 0.997 and a specificity of...
The most commonly used test for HIV has a sensitivity of 0.997 and a specificity of 0.985. In other words, a person infected with HIV will test positive for the virus 99.7% of the time while a person NOT infected with HIV will test NEGATIVE for the virus 98.5% of the time. Research current rates of infection for the indicated population in order to answer the following questions. 1. If a US randomly selected US resident is tested for HIV...
Suppose we assume that 5% of people are drug users. If a person is a drug...
Suppose we assume that 5% of people are drug users. If a person is a drug user, the result of the test is positive 95% of the time, and if the person is not a drug user, the result is negative 90% of the time. A person is randomly selected. What is the probability that he tests positive for drugs?
test for a certain disease is found to be 95% accurate, meaning that it will correctly...
test for a certain disease is found to be 95% accurate, meaning that it will correctly diagnose the disease in 95 out of 100 people who have the ailment. The test is also 95% accurate for a negative result, meaning that it will correctly exclude the disease in 95 out of 100 people who do not have the ailment. For a certain segment of the population, the incidence of the disease is 4%. (1) If a person tests positive, find...
Diagnostic tests of medical conditions can have several results. 1) The patient has the condition and...
Diagnostic tests of medical conditions can have several results. 1) The patient has the condition and the test is positive (+)             2) The patient has the condition and the test is negative (-) – Known as “false negative” 3) The patient doesn’t have the condition and the test is negative (-) 4) The patient doesn’t have the condition and the test is positive (+) – Known as “false positive” Consider the following:         Enzyme immunoassay (EIA) tests are used...
A new medical procedure has been shown to be effective in the early detection of a...
A new medical procedure has been shown to be effective in the early detection of a novel virus. A medical screening of the population is proposed. Let D denote the event that one has the disease, then D’ denotes the event that one doesn’t have the disease. Let + denote the event that the test signals positive, and – denote the event that the test signals negative. The probability that a new medical procedure correctly identifies someone with disease as...
A certain virus infects one in every 200200 people. A test used to detect the virus...
A certain virus infects one in every 200200 people. A test used to detect the virus in a person is positive 9090​% of the time when the person has the virus and 1010​% of the time when the person does not have the virus.​ (This 1010​% result is called a false positive​.) Let A be the event​ "the person is​ infected" and B be the event​ "the person tests​ positive." ​(a) Using​ Bayes' Theorem, when a person tests​ positive, determine...
A certain virus infects one in every 200 people. A test used to detect the virus...
A certain virus infects one in every 200 people. A test used to detect the virus in a person is positive 80​% of the time when the person has the virus and 15​% of the time when the person does not have the virus.​ (This 15​% result is called a false positive​.) Let A be the event​ "the person is​ infected" and B be the event​ "the person tests​ positive." ​(a) Using​ Bayes' Theorem, when a person tests​ positive, determine...