Find the mean and variance for each of the data in Exercise.
First n natural numbers
We know that Mean = 
∴ Mean, 
We know that Variance, σ2 = = 
We know that (a-b)2 = a2 – 2ab + b2
We know that (a + b) (a – b) = a2 – b2
Ans. Mean = 
and Variance = 
4