Stefan Tigges on Radiopaedia.org

Stefan Tigges

Professor of Radiology, Emory University School of Medicine

Thoracic Radiologist interested in education and using comics/drawing to teach. No pharmaceutical or medical device conflict of interest.

Disclosures:
  • Nothing to disclose
169 results found
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Question 2726

A trial comparing a new weight loss program to an old weight loss program reports that the new program results in 30 grams more weight loss than the old program with a p-value of 0.01.

What is the best interpretation of this result?

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Question 2727

A properly used and correctly calibrated blood pressure cuff is subject to what type of error?

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Question 2728

A clinical trial has a power of 80%. What is the probability that the trial will find an effect if one is present?

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Question 2729

A clinical trial has a power of 80%. What is the probability that the trial will miss an effect if one is present?

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Question 2730

What diagnostic test metric is most similar to clinical trial power?

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Question 2731

What does an increasing effect size do to the power of a clinical trial?

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Question 2732

What does increasing effect variability do to the power of a clinical trial?

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Question 2733

What is the most commonly used method to increase the power of a clinical trial?

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Question 2734

Why do clinical trials use randomization to allocate participants to different arms?

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Question 2735

Researchers announce that their study has found an association between the possession of matches and lung cancer. What is the most likely explanation for their results?

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Question 2851

What is the best definition of the "critical point" in the spread of cancer?

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Question 2852

What type of cancer screening bias may result from a cancer that never reaches the "critical point", i.e., the point at which it becomes difficult to cure?

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Question 2853

What type of cancer screening bias may result from a cancer that slowly reaches the "critical point", i.e., the point at which it becomes difficult to cure?

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Question 2854

What is the most characteristic feature of cancers that may lead to "length time" bias?

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Question 2855

What type of cancer screening bias(es) result(s) in overestimation of the benefits of screening?

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Question 2856

What type of cancer screening bias may result from a cancer that reaches the "critical point" (the point at which the cancer becomes difficult to cure) before it can be detected by screening?

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Question 2857

What study randomized >50,000 subjects into low-dose CT and chest x-ray screening groups and found a 20% reduction in lung cancer mortality in subjects screened with low-dose CT compared to chest x-ray screening?

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Question 2862

What is the correct notation for sensitivity stated as a conditional probability?

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Question 2863

What is the correct notation for specificity stated as a conditional probability?

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Question 2864

What is the correct notation for positive predictive value stated as a conditional probability?