Answer:
110
Step-by-step explanation:
We have been given that the mean IQ score is 100 and the standard deviation is 15.
We will use normal distribution table to solve our given problem.
The top 25% of the population will represent scores greater than 75%.
The z-score corresponding to data greater than 75% is 0.6745.
Upon substituting our given values in z-score formula, we will get:
Therefore, the top 25% of the population (ranked by IQ score) have IQ’s above 110.