Question 1205515
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The statement of the problem is faulty.<br>
The event of getting a head in 4 tosses of a fair coin is a single event.  "A head" means there is one head, so there are 3 tails, and the number of heads minus the number of tails is 1-3 = -2.<br>
So the very uninteresting probability distribution is<br>
P(-2) = 1<br>