I'm a little stuck on a problem and I know its most likely pretty easy.
I need to find the expected value of the number of heads after flipping a fair coin three times.
I know the probability for heads or tails is 1/2. I know the probability for each outcome of the three flips is 1/8. Just not really sure where to go from there.
E = p1*v1 + p2*v2 + ... + pn*vn, where
n means the amount of events,
p2 means the probality of the second event,
v2 means the value of the second event.
Now n = 4, because "the number of heads" can be 0, 1, 2 or 3.
So v1=0, v2=1, v3=2, v4=3.
p1 = p(nothing heads) = 1/8.
p4 = p(all heads) = 1/8.
p2 = p(exactly one head) = p(the first head others tails) + p(the second head others tails) + p(the 3th head others tails) = 1/8 + 1/8 + 1/8 = 3/8.
I leave for you p3 and E.
A bald statement like this is not very informative, explain why.
Originally Posted by Sean12345