In statistical theory, covariance is a measure of how much two random variables change together. In other words, covariance is a measure of the strength of the correlation between two random variables. Also, it can be considered as a generalization of the concept of variance of two random variables.
Facts & Figures. Lake Baikal is the largest freshwater lake by volume (23,600km3), containing 20% of the world's fresh water. At 1,637m, it is the deepest freshwater lake in the world; the average depth is 758m. It is 636km long and 81km wide; the surface area is 31,494km2. The lake is estimated to be 25 million years old, making it one of the most ancient lakes in geological history.
The Caspian Sea is the largest lake in the world by volume. It is also thought to be one of only a handful of ancient lakes on earth.It is generally believed that about 90 percent of all the world's sturgeons swim in the Caspian Sea.he Caspian Sea is the largest lake in the world by volume. It is also thought to be one of only a handful of ancient lakes on earth.