In testing a certain kind of missile, target accuracy is measured by the average distance X (from the target) at which the missile explodes. The distance X is measured in miles and the sampling distribution of X is given by:

X	0	10	50	100
P(X)	110	15	25	310

Calculate the variance of this sampling distribution.

a)52.0

b)438.7

c)2258.7

d)1316.0

e)36.3

f)None of the above