 # Skewness

Skewness:

Skewness measures the lack of symmetry of a probability distribution. A curve is said to be skewed to the right (or positively skewed) if it tails off toward the high end of the scale (right tail longer than the left). A curve is skewed to the left (or negatively skewed) if it tails off toward the low end of the scale.

Skewness of the distributions whose density is symmetrical around the mean is zero. The reverse is not true – there are asymmetrical distributions with zero skewness.

The skewness of a distribution is equal to its 3d central moment divided by the 3d power of the standard deviation.

Skewness characterizes the shape of a distribution – that is, its value does not depend on an arbitrary change of the scale and location of the distribution. For example, skewness of a sample (or population) of temperature values in Fahrenheit will not change if you transform the values to Celsius (the mean and the variance will, however, change).

Browse Other Glossary Entries

## Test Yourself

Planning on taking an introductory statistics course, but not sure if you need to start at the beginning? Review the course description for each of our introductory statistics courses and estimate which best matches your level, then take the self test for that course. If you get all or almost all the questions correct, move on and take the next test.

### Data Analytics

Considering becoming adata scientist, customer analyst or our data science certificate program?

Analytics Quiz

Statistics Quiz

### Statistics

Looking at statistics for graduate programs or to enhance your foundational knowledge?

Statistics 1 Quiz

Regression Quiz

Regression Quiz

### Biostatistics

Entering the biostatistics field? Test your skill here.

Biostatistics Quiz

Statistics 2 Quiz

### Stay Informed

Our Blog

Read up on our latest blogs

Certificates

Courses

Find the right course for you