Concept:Expected value is the weighted average of all possible values of a random variable.
Explanation:The expected value
E(X)=∑xi​pi​ can be any real number.
If the random variable takes only positive values with positive probability,
E(X)>0.
If it takes negative values,
E(X) can be negative.
If the distribution is symmetric about zero, e.g.,
X=−1 with
p=0.5 and
X=1 with
p=0.5, then
E(X)=0.
Thus, the expected value may be positive, negative, or zero.
Answer:Option C: may be positive or negative or zero.