Question

On an exam whose scores followed a normal distribution, a student's z-score was
+2.
What percentage of students scored better than he did? (Use the 68-95-99.7 Rule.)

Answer 1

Since you are only interested in number <I>above</I> Z = +2, you cannot apply the rule.

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion for that Z score. Multiply by 100.

Answer 2

42