Numeric.Probability.Example.Diagnosis

Description

You take part in a screening test for a disease that you have with a probability pDisease. The test can fail in two ways: If you are ill, the test says with probability pFalseNegative that you are healthy. If you are healthy, it says with probability pFalsePositive that you are ill.

Now consider the test is positive - what is the probability that you are indeed ill?

Synopsis

Documentation

type Probability = Rational Source

type Dist a = T Probability aSource

data State Source

Constructors

Healthy
Ill

Instances

Enum State
Eq State
Ord State
Show State

data Finding Source

Constructors

Negative
Positive

Instances

Enum Finding
Eq Finding
Ord Finding
Show Finding

pFalseNegative :: Probability Source

pFalsePositive :: Probability Source

pDisease :: Probability Source

dist :: Dist (State, Finding)Source

distAlt :: Dist (State, Finding)Source

Alternative way for computing the distribution. It is usually more efficient because we do not need to switch on the healthy state.

p :: Probability Source