If X is the number of tails in three tosses of a coin, determine the standard deviation of X.

Question

Philoid · Accepted Answer

Given that, Radom variable X is the member of tails in three tosses of a coin

So, X= 0,1,2,3

Where n=3, and x= 0,1,2,3

We know that, Var (X)= E(X²)- [E(X)]² ……(i)

Where, E(X²) =

=3

And

Putting the values of E(X)² and [E(X)]² in equation (i), we get:

And standard deviation of