What is a outlier?

Answer 1

You will be using your frontal left lobe of brain when doing any mathematical calculations or logical thinkings. At a point of time, when you are more into mathematics, you may start forgetting your family, miss your routine chores, lose your creativity skills, etc. Mathematics is indeed difficult, mathematicians (or people who have such brain) would be nerd, and the possibility of a mathematician to become a great leader is very low. I'm also learning mathematics to make my brain younger, without trying to miss the other aspects in life :)

Answer 2

Outliers are observations that are way out of line with other observations.

There are several definitions of outliers - based on the quartiles and the interquartile range. Values

smaller than Q1 - k*IQR

or

larger than Q3 + k*IQR

for some positive value k are considered outliers.

The definition may be asymmetrical if the variable is believed to be so distributed.