Suppose there are three balls in a box. on one of the balls is the number 1, on another is the number 2, and on the third is the number 3. you select two balls at random and without replacement from the box and note the two numbers observed. the sample space s consists of the three equally likely outcomes ((1,2), (1,3), (2,3)) (disregarding order). let x be the sum of the two balls selected. (a) what is the distribution for x? (b) what is the probability that the sum is at least 4? (c) what is the mean of x?