Purchase Solution

Probability Evidence of a Serious Illness

Not what you're looking for?

Ask Custom Question

A doctor finds evidence of a serious illness in a particular patient and must make a determination about whether or not to advise the patient to undergo a dangerous operation. If the patient does suffer from the illness in question, there is a 95% probability that he will die if he does not undergo the operation. If he does undergo the operation, he has a 50% probability of survival. If the operation is conducted and it is discovered that the patient does not suffer from the illness, there is a 10% probability that the patient will die due to complications resulting from the operation. If it has been estimated that there is a 20% to 30% probability of the patient actually having the illness in question, how should the doctor advise her patient?

Purchase this Solution

Solution Summary

The probability evidence of a serious illness is determined.

Solution Preview

Several points to make here:

First, I think you may have slightly misread the information given. The doctor has detected *evidence* of the illness. That is not the same as saying the doctor has detected the illness where you might have to worry about false positives. The question is basically saying that based on the evidence the doctor has found, there is a 20-30% chance the patient actually has the illness.

Second, the reason the probabilities in the chance tree don't add up to 1 is because you have effectively given both "surgery" and "no surgery" a probability of 1 (think of your final probabilities as having a multiplied by 1 part corresponding to that part of the chart). If you were to split out the chart into one chart for "surgery" and one chart for "no surgery", you'd see ...

Purchase this Solution


Free BrainMass Quizzes
Probability Quiz

Some questions on probability

Know Your Linear Equations

Each question is a choice-summary multiple choice question that will present you with a linear equation and then make 4 statements about that equation. You must determine which of the 4 statements are true (if any) in regards to the equation.

Exponential Expressions

In this quiz, you will have a chance to practice basic terminology of exponential expressions and how to evaluate them.

Geometry - Real Life Application Problems

Understanding of how geometry applies to in real-world contexts

Multiplying Complex Numbers

This is a short quiz to check your understanding of multiplication of complex numbers in rectangular form.