Tutoring statistics, the concept of skew arises. The tutor gives some brief ideas about skew.

The normal distribution isn’t skewed, because its left and right tails are simply mirror images of each other.

When a distribution’s left tail is longer than its right, we say that distribution is negatively skewed. In such a case you get a long left tail that ramps up to a clump of values on the right.

The opposite is true for a positively skewed distribution; most of the population is clumped to the left, but a long tail extends to the right.

Therefore, skew describes the location of the distribution’s longer tail: negative skew means long tail to the left (the negative) side, whereas positive skew means long tail to the right (positive) side.

HTH:)

Source:

Harnett, Donald L. and James L. Murphy. Statistical Analysis for Business and Economics, 3rd ed. Don Mills: Addison-Wesley, 1986.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.