and it is theretorevery important to obtain some estimate of disease prevalence.ExercisesA medical research team wishes to assess the usefulness of a certain symptom (call it S) inthe diagnosis of a particular disease. In a random sample of 775 patients with the disease,744 reported having the symptom. In an independent random sample of 1380 subjectswithout the disease, 21 reported that they had the symptom.(a) In the context of this exercise, what is a false positive?(b) What is a false negative?(c) Compute the sensitivity of the symptom.(d) Compute the specificity of the symptom.(e) Suppose it is known that the rate of the disease in the general population is. 001. Whatis the predictive value positive of the symptom?(f) What is the predictive value negative of the symptom?(g) Find the predictive value positive and the predictive value negative for the symptomfor the following hypothetical disease rates: .0001, .01, and .10.(h) What do you conclude about the predictive value of the symptom on the basis of theresults obtained in part g?3.5.1 SOME BASIC PROBABILITY CONCEPTSIn an article entitled "Bucket-Handle Meniscal Tears of the Knee: Sensitivity and Speci-ficity of MRI signs," Dorsay and Helms (A-5) performed a retrospective study of 71 kneesscanned by MRI. One of the indicators they examined was the absence of the "bow-tiesign" in the MRI as evidence of a bucket-handle or "bucket-handle type" tear of the menis-cus. In the study, surgery confirmed that 43 of the 71 cases were bucket-handle tears. Thecases may be cross-classified by “bow-tie sign" status and surgical results as follows:3.5.2Tear Surgically ConfirmedTear SurgicallyConfirmed (D)As Not Present (D)Total381048Positive Test(absent bow-tie sign) (T)5Negative Test(bow-tie sign present) (T)182343Total2871Source: Theodore A. Dorsay and Clyde A. Helms, "Bucket-handle Meniscal Tears of the Knee: Sensitivity andSpecificity of MRI Signs," Skeletal Radiology, 32 (2003), 266–272.(a) What is the sensitivity of testing to see if the absent bow tie sign indicates a meniscaltear?(b) What is the specificity of testing to see if the absent bow tie sign indicates a meniscaltear?(c) What additional information would you need to determine the predictive value of thetest?

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Asked Feb 11, 2020
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we went over these problems in class for our notes in review for our up and coming exam, I've been out sick with the flu all week can you guys please help me 

and it is theretore
very important to obtain some estimate of disease prevalence.
Exercises
A medical research team wishes to assess the usefulness of a certain symptom (call it S) in
the diagnosis of a particular disease. In a random sample of 775 patients with the disease,
744 reported having the symptom. In an independent random sample of 1380 subjects
without the disease, 21 reported that they had the symptom.
(a) In the context of this exercise, what is a false positive?
(b) What is a false negative?
(c) Compute the sensitivity of the symptom.
(d) Compute the specificity of the symptom.
(e) Suppose it is known that the rate of the disease in the general population is. 001. What
is the predictive value positive of the symptom?
(f) What is the predictive value negative of the symptom?
(g) Find the predictive value positive and the predictive value negative for the symptom
for the following hypothetical disease rates: .0001, .01, and .10.
(h) What do you conclude about the predictive value of the symptom on the basis of the
results obtained in part g?
3.5.1
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and it is theretore very important to obtain some estimate of disease prevalence. Exercises A medical research team wishes to assess the usefulness of a certain symptom (call it S) in the diagnosis of a particular disease. In a random sample of 775 patients with the disease, 744 reported having the symptom. In an independent random sample of 1380 subjects without the disease, 21 reported that they had the symptom. (a) In the context of this exercise, what is a false positive? (b) What is a false negative? (c) Compute the sensitivity of the symptom. (d) Compute the specificity of the symptom. (e) Suppose it is known that the rate of the disease in the general population is. 001. What is the predictive value positive of the symptom? (f) What is the predictive value negative of the symptom? (g) Find the predictive value positive and the predictive value negative for the symptom for the following hypothetical disease rates: .0001, .01, and .10. (h) What do you conclude about the predictive value of the symptom on the basis of the results obtained in part g? 3.5.1

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SOME BASIC PROBABILITY CONCEPTS
In an article entitled "Bucket-Handle Meniscal Tears of the Knee: Sensitivity and Speci-
ficity of MRI signs," Dorsay and Helms (A-5) performed a retrospective study of 71 knees
scanned by MRI. One of the indicators they examined was the absence of the "bow-tie
sign" in the MRI as evidence of a bucket-handle or "bucket-handle type" tear of the menis-
cus. In the study, surgery confirmed that 43 of the 71 cases were bucket-handle tears. The
cases may be cross-classified by “bow-tie sign" status and surgical results as follows:
3.5.2
Tear Surgically Confirmed
Tear Surgically
Confirmed (D)
As Not Present (D)
Total
38
10
48
Positive Test
(absent bow-tie sign) (T)
5
Negative Test
(bow-tie sign present) (T)
18
23
43
Total
28
71
Source: Theodore A. Dorsay and Clyde A. Helms, "Bucket-handle Meniscal Tears of the Knee: Sensitivity and
Specificity of MRI Signs," Skeletal Radiology, 32 (2003), 266–272.
(a) What is the sensitivity of testing to see if the absent bow tie sign indicates a meniscal
tear?
(b) What is the specificity of testing to see if the absent bow tie sign indicates a meniscal
tear?
(c) What additional information would you need to determine the predictive value of the
test?
help_outline

Image Transcriptionclose

SOME BASIC PROBABILITY CONCEPTS In an article entitled "Bucket-Handle Meniscal Tears of the Knee: Sensitivity and Speci- ficity of MRI signs," Dorsay and Helms (A-5) performed a retrospective study of 71 knees scanned by MRI. One of the indicators they examined was the absence of the "bow-tie sign" in the MRI as evidence of a bucket-handle or "bucket-handle type" tear of the menis- cus. In the study, surgery confirmed that 43 of the 71 cases were bucket-handle tears. The cases may be cross-classified by “bow-tie sign" status and surgical results as follows: 3.5.2 Tear Surgically Confirmed Tear Surgically Confirmed (D) As Not Present (D) Total 38 10 48 Positive Test (absent bow-tie sign) (T) 5 Negative Test (bow-tie sign present) (T) 18 23 43 Total 28 71 Source: Theodore A. Dorsay and Clyde A. Helms, "Bucket-handle Meniscal Tears of the Knee: Sensitivity and Specificity of MRI Signs," Skeletal Radiology, 32 (2003), 266–272. (a) What is the sensitivity of testing to see if the absent bow tie sign indicates a meniscal tear? (b) What is the specificity of testing to see if the absent bow tie sign indicates a meniscal tear? (c) What additional information would you need to determine the predictive value of the test?

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Expert Answer

Step 1

Since you have posted a question with multiple sub-parts, we will solve first three sub-parts for you. To get remaining sub-part solved please repost the complete question and mention the sub-parts to be solved.

Step 2

Given that,

In a random sample of 775 patients with the disease, 744 reported having the symptom. In an independent random sample of 1380 subjects without the disease, 21 reported that they had the symptom.

From the given details,

 

Positive disease

Negative disease

total

Positive test

744

21

765

Negative test

31

1359

1390

total

775

1380

2155

Step 3
  1. In the context of this exercise, please describe what is a false positive?

The answer is,

The false positive would be a patient ...

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