Suppose that 20% of dogs will associate a flash of light with a delayed treat given after the flash. 30 dogs are tested in the lab to see if they will learn this association.

Question

Suppose that 20% of dogs will associate a 	flash	of light with a delayed treat given after the	flash. 30 dogs are tested in the lab to see if they	will learn	this association.

anonymous · Answer

Let	X denote	the	number	of	dogs	(out	of	these	30)	that	learn	the	
association.

anonymous · Answer

Compute	the	expected	value and	standard	deviation	of	X

anonymous · Answer

Expected=6, but what is SD?

anonymous · Answer

How would you take SD?

kropot72 · Answer

The result follows a  binomial distribution with n = 30 and p = 0.2.
The standard deviation is given by:
$$\large S.D.=\sqrt{np(1-p)}$$