The mean score for a standardized test is 1700 points. The results are normally distributed with a standard deviation of 75 points. If 10,000 students take the exam, how many would you expect to score above 1850 points?

Question

e.cociuba · Answer

(1850 - 1700) / 75
= 150 / 75
= 2... 2 on the z-table equals to 0.9772. But this is for 1850 and below, we want above so

P[z > 2] = 1 - P[z < 2]
= 1 - 0.9772
= 0.0228

10000 * 0.0228
= 228, approximately 228 people will score above 1850  

ANSWER: 228 :)