/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 34 Delayed diagnosis of cancer is a... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Delayed diagnosis of cancer is a problem because it can delay the start of treatment. The paper "Causes of Physician Delay in the Diagnosis of Breast Cancer" (Archives of Internal Medicine \([2002]: 1343-1348)\) examined possible causes for delayed diagnosis for women with breast cancer. The accompanying table summarizes data on the initial written mammogram report (benign or suspicious) and whether or not diagnosis was delayed for 433 women with breast cancer. $$ \begin{array}{l|cc} & & \text { Diagnosis } \\ & \begin{array}{c} \text { Diagnosis } \\ \text { Delayed } \end{array} & \begin{array}{c} \text { Not } \\ \text { Delayed } \end{array} \\ \hline \begin{array}{l} \text { Mammogram Report Benign } \\ \text { Mammogram Report } \\ \text { Suspicious } \end{array} & 32 & 89 \\ & 8 & 304 \\ \hline \end{array} $$ Consider the following events: \(B=\) the event that the mammogram report says benign \(S=\) event that the mammogram report says suspicious \(D=\) event that diagnosis is delayed a. Assume that these data are representative of the larger group of all women with breast cancer. Use the data in the table to find and interpret the following probabilities: i. \(\quad P(B)\) ii. \(P(S)\) iii. \(P(D \mid B)\) iv. \(P(D \mid S)\) b. Remember that all of the 433 women in this study actually had breast cancer, so benign mammogram reports were, by definition, in error. Write a few sentences explaining whether this type of error in the reading of mammograms is related to delayed diagnosis of breast cancer.

Short Answer

Expert verified
Calculated probabilities are as follows: \(P(B)\) refers to the probability of a benign mammogram report, \(P(S)\) refers to the probability of a suspicious mammogram report, \(P(D|B)\) represents the probability of a delayed diagnosis given a benign mammogram report while \(P(D|S)\) signifies the probability of a delayed diagnosis given a suspicious mammogram report. From comparison of \(P(D|B)\) and \(P(D|S)\), it can be reasoned whether there is a connection between errors in mammogram reading and delayed diagnosis.

Step by step solution

01

Calculation of P(B)

First calculate the probability of a benign mammogram report (\(P(B)\)) by adding up cases with benign mammogram reports (32 + 89) and dividing by total number of cases (32 + 89 + 8 + 304).
02

Calculation of P(S)

Next, calculate the probability of a suspicious mammogram report (\(P(S)\)) by summing cases with suspicious mammogram reports (8 + 304) and dividing by the total number of cases.
03

Calculation of P(D|B)

Now calculate the conditional probability of delayed diagnosis given a benign mammogram report (\(P(D|B)\)). This can be found by dividing instances of delayed diagnosis (32) with benign mammogram report by total instances of benign mammogram report (32 + 89).
04

Calculation of P(D|S)

Next calculate the conditional probability of delayed diagnosis given a suspicious mammogram report (\(P(D|S)\)). This can be calculated by dividing instances of delayed diagnosis (8) with suspicious mammogram report by total instances of suspicious mammogram report (8 + 304).
05

Interpretation of error in mammogram reading and delayed diagnosis

Finally, interpret the connection between errors in mammogram reading and delayed diagnosis. This can be understood through a comparative analysis of probabilities \(\(P(D|B)\) and \(\(P(D|S)\)

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Conditional Probability
Conditional probability helps us determine the likelihood of an event occurring, given that another event has already happened. In this exercise, we look at how this applies to understanding breast cancer diagnosis.

The conditional probability of delayed diagnosis given a benign mammogram report, denoted as \(P(D|B)\), can be calculated. With a benign report, the diagnosis delay probability is found by dividing the cases with both benign reports and delayed diagnosis by the total number of benign reports. This answers the question: How likely is a delayed diagnosis if the mammogram is benign?

To better grasp the full picture, we can also calculate \(P(D|S)\), the probability of a delayed diagnosis given a suspicious report. By comparing \(P(D|B)\) and \(P(D|S)\), we see how the mammogram reading, whether benign or suspicious, affects the delay in diagnosis.
Diagnostic Error
Diagnostic errors refer to false results from tests or reports that can lead to incorrect patient management. In the case of breast cancer, a benign mammogram report that turns out to be incorrect, because cancer actually exists, is a diagnostic error.

Such errors are critical in the medical field as they can lead to delayed treatments. Women who receive a benign mammogram report when they actually have cancer may not seek further medical advice as quickly, resulting in delayed diagnosis. This type of diagnostic error demonstrates how crucial accurate mammogram readings are to ensure timely intervention.

Understanding these errors through conditional probabilities allows researchers and practitioners to assess and improve diagnostic practices.
Breast Cancer
Breast cancer is a disease where cells in the breast grow uncontrollably. Timely diagnosis is crucial in managing and treating breast cancer effectively. This is why diagnostic accuracy is so important.

In this exercise, we investigate mammogram reports and their link to delayed diagnoses, which can drastically affect treatment outcomes. Early diagnosis and treatment are vital in breast cancer care because they often lead to better prognoses and higher survival rates.

One of the challenges is distinguishing benign from malignant cases. Errors in identifying these can radically alter treatment paths. Thus, understanding breast cancer-related probabilities assists healthcare providers in making informed decisions based on statistical data.
Statistical Analysis
Statistical analysis involves examining data to identify patterns and draw conclusions. In this context, it helps quantify the relationship between mammogram readings and diagnostic delays.

The probabilities \(P(B)\) and \(P(S)\) help us understand the distribution of benign and suspicious reports among patients. By calculating these, researchers can observe general trends in mammogram accuracy.

Statistical analysis provides a foundation for researchers to recommend changes in diagnostic approaches. When we understand the likelihood of delays due to diagnostic errors, strategies can be adapted to reduce these chances, thus enhancing healthcare outcomes.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The National Public Radio show Car Talk has a feature called "The Puzzler." Listeners are asked to send in answers to some puzzling questions-usually about cars but sometimes about probability (which, of course, must account for the incredible popularity of the program!). Suppose that for a car question, 800 answers are submitted, of which 50 are correct. a. Suppose that the hosts randomly select two answers from those submitted with replacement. Calculate the probability that both selected answers are correct. (For purposes of this problem, keep at least five digits to the right of the decimal.) b. Suppose now that the hosts select the answers at random but without replacement. Use conditional probability to evaluate the probability that both answers selected are correct. How does this probability compare to the one computed in Part (a)?

Suppose that a six-sided die is "loaded" so that any particular even-numbered face is twice as likely to land face up as any particular odd-numbered face. Consider the chance experiment that consists of rolling this die. a. What are the probabilities of the six simple events? (Hint: Denote these events by \(O_{1}, \ldots, O_{6}\). Then \(P\left(O_{1}\right)=p, P\left(O_{2}\right)=2 p, P\left(O_{3}\right)=p, \ldots, P\left(O_{6}\right)=2 p\) Now use a condition on the sum of these probabilities to determine \(p\).) b. What is the probability that the number showing is an odd number? at most three? c. Now suppose that the die is loaded so that the probability of any particular simple event is proportional to the number showing on the corresponding upturned face; that is, \(P\left(O_{1}\right)=c, P\left(O_{2}\right)=2 c, \ldots\), \(P\left(O_{6}\right)=6 c\). What are the probabilities of the six simple events? Calculate the probabilities of Part (b) for this die.

In an article that appears on the web site of the American Statistical Association (www.amstat.org), Carlton Gunn, a public defender in Seattle, Washington, wrote about how he uses statistics in his work as an attorney. He states: 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 \(T D=\) event that the test result is dirty, \(T C=\) event that the test result is clean, \(D=\) event that the person tested is actually dirty, and \(C=\) event that the person tested is actually clean. a. Using the information in the quote, what are the values of \mathbf{i} . ~ \(P(T D \mid D)\) iii. \(P(C)\) ii. \(P(T D \mid C)\) iv. \(P(D)\) b. Use the law of total probability to find \(P(T D)\). c. Use Bayes' rule to evaluate \(P(C \mid T D)\). Is this value consistent with the argument given in the quote? Explain.

A bookstore sells two types of books (fiction and nonfiction) in several formats (hardcover, paperback, digital, and audio). For the chance experiment that consists of observing the type and format of a single-book purchase, two possible outcomes are a hardcover fiction book and an audio nonfiction book. a. There are eight outcomes in the sample space for this experiment. List these possible outcomes. b. Do you think it is reasonable to think that the outcomes for this experiment would be equally likely? Explain. c. For customers who purchase a single book, the estimated probabilities for the different possible outcomes are given in the cells of the accompanying table. What is the probability that a randomly selected single-book purchase will be for a book in print format (hardcover or paperback)? $$ \begin{array}{l|cccc} {\text { Hardcover }} & \text { Paperback } & \text { Digital } & \text { Audio } \\ \hline \text { Fiction } & .15 & .45 & .10 & .10 \\ \text { Nonfiction } & .08 & .04 & .02 & .06 \\ \hline \end{array} $$ d. Show two different ways to compute the probability that a randomly selected single-book purchase will be for a book that is not in a print format. e. Find the probability that a randomly selected singlebook purchase will be for a work of fiction.

There are two traffic lights on the route used by a certain individual to go from home to work. Let \(E\) denote the event that the individual must stop at the first light, and define the event \(F\) in a similar manner for the second light. Suppose that \(P(E)=.4, P(F)=.3\), and \(P(E \cap F)=.15\) a. What is the probability that the individual must stop at at least one light; that is, what is the probability of the event \(E \cup F\) ? b. What is the probability that the individual needn't stop at either light? c. What is the probability that the individual must stop at exactly one of the two lights? d. What is the probability that the individual must stop just at the first light? (Hint: How is the probability of this event related to \(P(E)\) and \(P(E \cap F)\) ? A Venn diagram might help.)

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.