Literally, skewness means lack of symmetry. We study skewness to have an idea about the shape of the curve which we can draw with the help of the given data. A distribution is said to be skewed if
i) Mean, median and mode fall at different points
ii) Quartiles are not equidistant from median, and
iii) The curve drawn with the help of the given data is not symmetrical but stretched more to one side than to the other.