Sensitivity index
（重定向自Discriminability index）
The sensitivity index or d' (pronounced 'dee-prime') is a statistic used in signal detection theory. It provides the separation between the means of the signal and the noise distributions, compared against the standard deviation of the signal plus noise distributions. For normally distributed signal and noise with mean and standard deviations ![\mu _{S}](/Images/godic/202501/09/1bcf70432a8e073db589ac5a3cb9f6aa0956.png")
and ![\sigma _{S}](/Images/godic/202501/09/6f40b9e03fc1c2ad0453af4aabd98aac0956.png")
, and ![\mu _{N}](/Images/godic/202501/09/47a09c152633efc2b60abd9ee3bc19560956.png")
and ![\sigma _{N}](/Images/godic/202501/09/0da6b0c9545094a41f80284af5cd33340956.png")
, respectively, d' is defined as: