Conditional Probability Medical Testing

7.3 – Conditional Probability and Evidence Based Medicine

https://biostatistics.letgen.org/mikes-biostatistics-book/probability-risk-analysis/conditional-probability-and-evidence-based-medicine/

The doctor is reviewing results from a diagnostic test, e.g., a FOBT — fecal occult blood test — a test used as a screening tool for colorectal cancer (CRC). The doctor knows that the test has a sensitivity of about 75% and specificity of about 90%. Prevalence of CRC …

Diagnostic tests: how to estimate the positive predictive …

https://academic.oup.com/nop/article/2/4/162/2460002

Approach 1: Conditional Probability Equations. Conditional probabilities are important in the interpretation of diagnostic tests because the test results influence our …

statistics - Conditional Probability for a Medical Test

https://math.stackexchange.com/questions/4173078/conditional-probability-for-a-medical-test

there is a probability of 0.8 − 0.35 = 0.45 the fast test shows negative and the slow test positive. there is a probability of 1 − 0.35 − 0.05 − 0.45 = 0.15 both tests …

Conditional Probability: Definition, Formula & Examples

https://statisticsbyjim.com/probability/conditional-probability/

Conditional Probability - Stanford University

https://web.stanford.edu/~dntse/classes/cs70_fall09/n11.pdf

Conditional Probability A pharmaceutical company is marketing a new test for a certain medical condition. According to clinical trials, the test has the following properties: 1. …

Understanding Medical Tests and Test Results - Special …

https://www.merckmanuals.com/professional/special-subjects/clinical-decision-making/understanding-medical-tests-and-test-results

For a given test, the LR is different for positive and negative results. For example, given a positive test result, an LR of 2.0 indicates the odds are 2:1 (true positives:false positives) …

Bayes’ Theorem for Medical Tests

https://towardsdatascience.com/bayes-theorem-for-medical-test-f1fb12b579c6

We can now apply the formula to compute the conditional probability: P(G∣S) = P(G)P(S∣G)/p(S) = 0.4×0.5/0.8 = 0.25 → 25%. ... Of these for the sensitivity and specificity are the …

Bayes's Theorem - Boston University

https://sphweb.bumc.bu.edu/otlt/MPH-Modules/BS/BS704_Probability/BS704_Probability6.html

We can compute this conditional probability with the available information using Bayes Theorem. By substituting the probabilities in this scenario, we get: Thus, …

Medical False Positives and False Negatives

https://brownmath.com/stat/falsepos.htm

Summary: If a test for a disease is 98% accurate, and you test positive, the probability you actually have the disease is not 98%. In fact, the more rare the disease, …

Medical Test: Conditional Probability, Bayes' Theorem

https://www.youtube.com/watch?v=pC8yj7FFi-4

A quick and informal introduction to the notion of conditional probability and its main mathematical property: Bayes' Theorem. This is demonstrated using the...