Posted by Jackie on .
For a Normal distribution with mean, mu=2, and standard deviation, sigma = 4,
70% of all observations have values between x and y . (Round to 4 decimal places.)

Math 
Steve,
Consult your standard Z table. 35% of all observations occur between 0 and 1.04σ. So, 70% occur between 1.04σ and 1.04σ.
So, that means that the actual values occur in
21.04(4) <= x <= 2+1.04(4)
2.16 <= x <= 6.16