The formula for determining the mean from the probability distribution table is expressed as mean = summation(x * P(x))
Thus, we have
x | p(x) | xp(x)
3 | 0.14 | 0.42
6 | 0.05 | 0.3
9 | 0.36 | 3.24
12 | 0.35 | 4.2
15 | 0.10 | 1.5
Mean = 0.42 + 0.3 + 3.24 + 4.2 + 1.5 = 9.66
The last option is correct.
