Question

In: Biology

For this discussion board, you will be presented with information about a new screening test. Scenario:...

For this discussion board, you will be presented with information about a new screening test.

Scenario: A new hypothetical instantaneous screening test for marijuana has been developed to identify people driving under the influence. 100 drivers are stopped by police and screened. 15 people were actually under the influence of marijuana, while the remainder were not. Of the 15 under the influence, only 10 tested positive. Of those who were not under the influence, 40 tested positive.

Instructions initial post: For your post, please complete the following questions. Be sure to set up your two-by-two table. In your post, you must correctly explicitly state the context of every numeric answer by including a sentence of interpretation (for example: "98% of patients who truly have breast cancer will have a positive mammography screen")

  1. What is the prevalence of driving under the influence of marijuana?
  2. Calculate sensitivity and interpret.
  3. Calculate specificity and interpret
  4. Calculate positive predictive value and interpret.
  5. If more people drove under the influence of marijuana, how would the positive predictive value change?
  6. Calculate negative predictive value
  7. Calculate the accuracy of the screening tool.

In addition to posting your answers to the above questions, use those answers to write an opinion about:

  1. whether or not this is a reasonable screening tool for police to use to enforce laws regarding driving under the influence and why.
  2. how this screening tool could be improved.

Solutions

Expert Solution

Answer-

The prevalence is 15% . It is the total number of individuals who are under the influence of marijuana . It is a+c x100.

Interpretations-

Sensitivity -66.6% individuals were under the influence of marijuana and tested positive for it.

Specificity - 52.9% were not under the influence of marijuana and tested Negative for it.

Positive predictive value- there is 20% chance that the individual tested positive for the test was actually under influence of marijuana.

Negative predictive value - 90% chance that an individual tested negative for the test actually is not under influence of marijuana.

If more people drove under the influence of marijuana,the positive predictive value will increase. It increases with increase in prevalance.

This screening tool has only 55% accuracy .the specificity is 53% and sensitivity is 67% . A good screening tool will have a sensitivity and specificity of 99.9% . Which would mean all the individuals tested positive will actually have the disease and 99% times individuals tested negative wont have the disease or influence of drugs. This screening tool is not reliable to enforce laws . It can be improved by increasing the specificity and sensitivity.

If this helps please give it a positive rating thank you!


Related Solutions

In this discussion board activity, begin by rereading the scenario about the imminent merger presented in...
In this discussion board activity, begin by rereading the scenario about the imminent merger presented in the first paragraph of the Blackboard lecture on Moral Philosophies (located on course content page under Business Ethics) and complete the assigned posting listed below. Pretend that you are the person that found the merger information and must decide what to do with it. FOCUS on the ethical NOT the legal issues. Select one (and only one) of the three approaches presented for dealing...
Discussion board information about the importance of subcategories of net assets
Discussion board information about the importance of subcategories of net assets
Read the following scenario and answer the questions that follow in the discussion board area of...
Read the following scenario and answer the questions that follow in the discussion board area of class. Provide a thoughtful and informative response to the questions; you should be able to support your recommendations. Be sure to support your ideas with evidence gathered from reading the text or other outside sources. Be sure to give credit to the sources where you find evidence. Use an attribution like "According to the text," or "According to Computer Weekly website" in your response....
In this final discussion board post, I want you to research a new and controversial method...
In this final discussion board post, I want you to research a new and controversial method for extracting oil and gas, fracking. The expansion of this unconventional method for extracting oil and gas has lead to a domestic 'boom' lowering our dependence on foreign oil.  But does it come at a cost? For this post, I want you to research what fracking is, and identify the pros and cons of this form of energy extraction.  Choose a side of the...
A new test is being assessed as a rapid screening tool for HIV+ status. In a...
A new test is being assessed as a rapid screening tool for HIV+ status. In a sample of 483 persons, 50 are HIV+ as defined by traditional assays. Of these 50, the new screening test was positive for 40 persons. Of those HIV- (as defined by traditional assays), the new screening test was negative for 416 persons. Fill in the table (5 points)                                                     Gold Std- Traditional Test HIV + HIV- total + - Total                                                                                                                         a. What is...
Screening for early detection of lung cancer is a new concept. How do you feel about...
Screening for early detection of lung cancer is a new concept. How do you feel about performing this screening for clients who are current or former smokers? What would you advise a man over 50 who is reluctant to be screened for prostate cancer?
For this Discussion, think of a specific testing scenario. Then consider a reliable test item for...
For this Discussion, think of a specific testing scenario. Then consider a reliable test item for that testing scenario and an unreliable item for that same testing scenario. Consider how you might know if these items are reliable or unreliable. With these thoughts in mind: Post a brief description of a specific testing scenario. Then describe one reliable test item and one unreliable test item for that testing scenario. Finally, explain what determines whether an item is reliable or unreliable...
a new screening test for Lyme disease is being evaluated. it was administered to 1,235 people...
a new screening test for Lyme disease is being evaluated. it was administered to 1,235 people in maine. While 115 people with the disease tested positive for it another 47 people who do not have the disease tested positive for Lyme. 721 people who do not have Lyme tested negative. 1. calculate specificity 2. calculate positive predictive value 3. calculate the negative predictive value 4. would you recommend this nrw screening test?
This assignment is about correlations and test of hypothesis. For each test of hypothesis scenario, (a)...
This assignment is about correlations and test of hypothesis. For each test of hypothesis scenario, (a) formulate the null and alternative hypotheses, (b) indicate the test used, (c) state the p-value from the test results, and (d) provide your conclusion. In your conclusion, give a reason for rejecting or not rejecting the null and clearly state what it means in the context of the problem. Are there significant differences in current salary for men and women? Female Male $21,900.00 $57,000.00...
A new screening test for Type II diabetes was evaluated/validated based on a group of 800...
A new screening test for Type II diabetes was evaluated/validated based on a group of 800 persons, 20% of whom were known to have the disease based on a previous diagnosis. Validation results included the following: (1) the screening test accurately identified 140 persons as having the disease; (2) the screening test accurately ruled out 500 persons as NOT having the disease. (A)      What is the estimated sensitivity of the new screening test? (B)      What is the estimated specificity of the new...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT