Variance & SD— How far Spreaded !!

Lets check how spread or disperse out our data is ?

Well, we all love to travel for sure. In case if you ever travelled from Asian countries to Europe or may be Asia to any western countries, have you ever noticed that most of connecting flights are from Middle East ( Dubai or Sharjah mostly ). Why ??

Answer is variance from centre ( Middle East ) or mean distance from these countries are less.

Holds true for Paris as well 😁

For more read Hub-and-Spoke Model which reduces the overall variance.

But let’s take one step back and will see why we need the variance, if we have the mean, median or mode as great representative of data ?

If someone gave you the 1-number summary (central tendency) of the below shown five datasets, in your mind, you would have thought they all are the same since their means are the same but when you plot each data point of each set and compare them visually you will realise that there should exist a…