Mode and Dispersion of the Length of Life

Kannisto Vâino.- Mode and Dispersion of the Length of Life The mode is both a natural measure of the length of life and a good basis for measuring its dispersion. Empirical data show that when the distribution on the right side of the mode is replicated symmetrically on the left, the result is a close approximation to the normal curve already postulated by Lexis. As the mode moves to higher ages, the dispersion above it is steadily reduced. Indicators giving the shortest age interval in which a given proportion of all deaths occur, prove that transition from high to low mortality is accompanied by massive compression which later slows down.