- I was provided with the exam results for GE 402 . The data follows a normal distribution with N(87,2) what is the probability that I got between 85 and 90 ? Solution 1: step 1: plot N(87,2) and find the area under the curve at 90 or less step 2 plot N(87,2) and find the area under the curve at 85 or less step 3: subtract the first area from the second area.