A probability distribution is a statistical technique that mathematically graphs the probability of particular events. While many of these statistical graphs resemble a bell (with the full range of possibilities being roughly the same on both sides of the mean; called a normal curve or normal distribution, a negatively skewed distribution will show smaller points farther away from the mean (on the left-hand side of the graph) than the larger numbers on the right side of the graph. Negatively skewed distribution is a statistical term frequently used in statistics and probability distributions to describe how scores or data are represented.
For example, a negatively skewed distribution would be expected if a teacher were to give an 8th grade achievement test to a classroom of 3rd graders. Some of the students might be able to answer some of the questions but most would fail the quiz therefore leading to a serious skew on the left side of the mean.