D'
Encyclopedia
The sensitivity index or d' is a statistic
used in signal detection theory. It provides the separation between the means of the signal and the noise distributions, in units of the standard deviation of the noise distribution.
An estimate of d' can be found from measurements of the hit rate and false-alarm
rate. It is calculated as:
where function Z(p), p ∈ [0,1], is the inverse of the cumulative Gaussian distribution.
A higher d indicates that the signal can be more readily detected.
Statistic
A statistic is a single measure of some attribute of a sample . It is calculated by applying a function to the values of the items comprising the sample which are known together as a set of data.More formally, statistical theory defines a statistic as a function of a sample where the function...
used in signal detection theory. It provides the separation between the means of the signal and the noise distributions, in units of the standard deviation of the noise distribution.
An estimate of d' can be found from measurements of the hit rate and false-alarm
False alarm
A false alarm, also called a nuisance alarm, is the fake report of an emergency, causing unnecessary panic and/or bringing resources to a place where they are not needed. Over time, repeated false alarms in a certain area may cause occupants to start to ignore all alarms, knowing that each time it...
rate. It is calculated as:
-
- d = Z(hit rate) - Z(false alarm rate),
where function Z(p), p ∈ [0,1], is the inverse of the cumulative Gaussian distribution.
A higher d indicates that the signal can be more readily detected.
External links
- Interactive signal detection theory tutorial including calculation of d'.