For the probability density function f defined on the random variable x, find (a) the mean of x, (b) the standard deviation of x, and (c) the probability that the random variable x is within one standard deviation of the mear 1 f(x)=2x. (5.7] a) Find the mean. p= (Round to three decimal places as needed.) b) Find the standard deviation. G= (Round to three decimal places as needed.) c) Find the probability that the random variable x is within one standard deviation of the mean. The probability is (Round to three decimal places as needed.)