Question 401552
a.  553 and 1153.(Corresponds to 3 SD's on both sides of the mean.)

b.  {{{(3/4)*100}}}% = 75%.  (Corresponding to 2 SD's on both sides of the mean.)

c.  95% according to the 68 - 95 - 99.7 (empirical) rule. (Corresponding to 2 SD's on both sides of the mean.)

d. 753 and 953 (Corresponding to 1 SD on both sides of the mean.)