Skewed distribution

A bell shaped curve on a graph is symmetrical and has no skew. The peak of the graph is in the centre and the tails either side of the peak are a mirror image of each other. The mean, median and mode are all in the same position on the graph (right through the centre of the peak).

This is an example of an evenly distributed bell curve with the mode going through the centre

When a graph is said to be skewed, this refers to the tail and not the peak of the graph. In a left skewed graph (also known as a negative skew) the mean is to the left of the median, whereas in a right skewed graph (also known as positive skew) the mean is to the right of the median, as can be seen below:

These are examples of uneven or skewed distribution of bell curves but note the mode still marks the very top of the curve, always