Signal-to-noise statistic

In mathematics the signal-to-noise statistic distance between two vectors a and b with mean values $$\mu _a$$ and $$\mu _b$$ and standard deviation $$\sigma _a$$ and $$\sigma _b$$ respectively is:


 * $$D_{sn} = {(\mu _a - \mu _b) \over (\sigma _a + \sigma _b)}$$

This distance is frequently used to identify vectors that have significant difference. One usage is in bioinformatics to locate genes that are differential expressed on microarray experiments.