The median of the results was 80 points out of 100, with a standard deviation of 6 points. which of the following numbers is closest to the number of students that got more than 86 but less than 92 points?
1
3
7
9

Z-score is a statistical tool that is used to estimate the probability of finding a number in a normal distribution of data. A normal distribution is described as a function in which the mean is zero, the standard deviation is 1 and that the area under the curve is equal to 1. 

The z-score at 86 is z = (86-80)/6 = 1. the probability to the right is 0.1587. 
The z-score at 92 is z = (92-80)/6 = 2. the probability to the left is 0.9772. 
The difference in probability is equal to 0.8185. We multiply this to the number of total students to get the answer.