Here, by default both apt-cache and aptitude search for a package on whole list of packages in repository, but output of aptitude shows whether the package is installed on the system or not by giving a per-package flag which here is 'p' indicating that package is present but not installed and 'i' which indicates that the package is installed, whereas apt-cache just lists the package and its one-line detail without telling if package is installed or not.
deviation deÂ·viÂ·aÂ·tion (dÄ'vÄ-Ä'shÉn) n. A turning away or aside from a normal course. An abnormality. Deviant behavior or attitudes. The difference, especially the absolute difference, between one number in a set and the mean of the set.
DEFINITION of 'Standard Deviation'. 1. A measure of the dispersion of a set of data from its mean. The more spread apart the data, the higher the deviation. Standard deviation is calculated as the square root of variance.2. In finance, standard deviation is applied to the annual rate of return of an investment to measure the investment's volatility. measure of the dispersion of a set of data from its mean. The more spread apart the data, the higher the deviation. Standard deviation is calculated as the square root of variance.