The standard score of a raw score x is. where: The absolute value of z represents the distance between the raw score and the population mean in units of the standard deviation. z is negative when the raw score is below the mean, positive when above. A key point is that calculating z requires the population mean and the population standard deviation, not the sample mean or sample deviation.
The definition of a siren is a wailing sound made by passing air through a rotating disc, or a beautiful woman who uses sex to attract men, or a mythical female creature that lures men into the sea. 1  An example of a siren is the sound from a police car as it moves through traffic.
Middle English (denoting an imaginary type of snake): from Old French sirene, from late Latin Sirena, feminine of Latin Siren, from Greek SeirÄn. More. In classical mythology the Sirens were bird-women whose beautiful singing lured sailors to their doom on submerged rocks.People hear a siren song or siren call when they are attracted to something that is both alluring and potentially harmful or dangerous.iddle English (denoting an imaginary type of snake): from Old French sirene, from late Latin Sirena, feminine of Latin Siren, from Greek SeirÄn. More. In classical mythology the Sirens were bird-women whose beautiful singing lured sailors to their doom on submerged rocks.