Definition:

Consider some population where the measurement of interest is some numeric quantity. We refer to the dispersion of this measurement over the range of measurements as the distribution of the population.

Note:
We are often interested in the shape of a distribution. That is, the "smoothed" surface defined by the top of the columns of the associated histogram. Many populations in the real world have a mound shaped distribution. We are particularly interested in two such distributions:

• The Normal distribution.
• The Student t distribution.