Determine whether the distribution represents a probability distribution, explain your answer

Question

X 1 2 3 5

P(×) ¼ ⅛ ¼ ⅛

Answer 1

1/4 + 1/4 + 1/8 +1/8 = 3/4, not 1

they need to sum to 1 to be a probability function

unless there's also a 4 where P(4)= 1/8

then the probabilities sum to 1 or 100%

P(1) =1/4 = 25%

P(2) = 1/8 = 12.5%

P(3) = 1/4 = 25%

P(4) = 1/8 = 12.5%

P(5) = 1/8 = 12.5%

add them up they sum to 100%