8/13 =0.53 (likely)
8 (navy marbles) over the total amount of marbles = 0.53
0=impossible
between 0 and 0.25 =likely impossible
between 0.25 and 0.50 = less likely
0.50 = equal , even, or same
between 0.50 ans 0.75 = likely
between 0.75 and 1 = most likely
1 = certain