I believe the answer given is wrong for the following question:

My answer is $\displaystyle \mu = 6, \sigma \approx 2.28$. The book says that $\displaystyle \sigma = 2.19$. Who's right?Quote:

Determine the mean and standard deviation of the random variable whose probability distribution is

x = 2, P(x) = .1

x = 4, P(x) = .2

x = 6, P(x) = .4

x = 8, P(x) = .2

x = 10, P(x) = .1