The charts show the stature distributions in two different samples of the same population. The first sample has 10 observations, the second sample has 1,000 observations. In the first chart, the distribution is skewed and in the second, the distribution is symmetrical.

Joining the middle higher points of each bar, we obtain the figure knows as Normal distribution.

This distributions is the more important in statistics; it is called also, Gaussian distribution.

All Normal distributions have a bell form and are defined for their mean and their standard deviation.

If the mean increase, the distribution move to the right; if the mean diminish, the distribution move to the left.

If the standard deviation increase, the dispersal and the width of the distribution increase and the high, diminish; if the standard deviation diminish, dispersal and width of the distribution diminish and the high of distribution increase.