Formula to represent 'equality' I am trying to find the appropriate formula in order to calculate and represent the 'equality' between a set of values. Let me explain with an example:
Imagine 3 people speaking on an a TV Show that lasts 45 minutes:
Person 1 -> 30 minutes spoken
Person 2 -> 5 minutes spoken
Person 3 -> 10 minutes spoken
I want to find a number that expresses how "equal" was this discussion in matters of time spoken per person. The ideal would be to speak 15 minutes each (100% equality) and the worst case scenario would be to speak only one person for 45 minutes (0% equality).
My first thought, is to use the standard deviation. When the standard deviation is 0 we have perfect equality. As the standard deviation gets larger, the equality is reduced.
The problem with standard deviation, is that is not easily readable for a person who is not familiar with statistics. Can you think of a formula that can help me represent the standard deviation (maybe in conjunction with the mean) as a percentage between 0% and 100% ?

Finally, thanks to @Rahul, found Gini Coefficient which works great for my case. 

The Gini coefficient (also known as the Gini index or Gini ratio)
  (/dʒini/ jee-nee) is a measure of statistical dispersion intended to
  represent the income distribution of a nation's residents, and is the
  most commonly used measure of inequality

https://en.wikipedia.org/wiki/Gini_coefficient
