Thread: Standard deviation of a random variable

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

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

My answer is . The book says that . Who's right?

Originally Posted by earachefl

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



My answer is . The book says that . Who's right?

The book (assuming you have right).

RonL

argghhh.... stupid math error....