Blood diamonds. according to global research news (mar. 4, 2014), one-fourth of all rough diamonds produced in the world are blood diamonds, i. e., diamonds mined to finance war or an insurgency. in a random sample of 700 rough diamonds purchased by a diamond buyer, let x be the number that are blood diamonds. a. find the mean of x. b. find the standard deviation of x. c. find the z-score for the value x = 200. d. find the approximate probability that the number of the 700 rough diamonds that are blood diamonds is less than or equal to 200.