Skewed

Skewed

A distribution that is skewed right (also known as positively skewed) is shown below.

Now the picture is not symmetric around the mean anymore.For a right skewed distribution, the mean is typically greater than the median.Also notice that the tail of the distribution on the right hand (positive) side is longer than on the left hand side.

From the box and whisker diagram we can also see that the median is closer to the first quartile than the third quartile.The fact that the right hand side tail of the distribution is longer than the left can also be seen.

A distribution that is skewed left has exactly the opposite characteristics of one that is skewed right:

• the mean is typically less than the median;
• the tail of the distribution is longer on the left hand side than on the right hand side; and
• the median is closer to the third quartile than to the first quartile.

The table below summarises the different categories visually.

Symmetric	Skewed right (positive)	Skewed left (negative)