Final answer:
In a normal distribution with a mean of 20 and a standard deviation of 5, approximately 68% of people would score between 15 (one standard deviation below the mean) and 25 (one standard deviation above the mean), according to the empirical rule.
Step-by-step explanation:
The mean score on a creativity test is 20 and the standard deviation is 5. The distribution is normal. To find how many people would attain a score between 15 and 25, we use the properties of the normal distribution, specifically the empirical rule or the 68-95-99.7 rule.
A score of 15 is one standard deviation below the mean, while a score of 25 is one standard deviation above the mean. According to the empirical rule, approximately 68% of the data falls within one standard deviation of the mean for a normal distribution. Therefore, we can estimate that 68% of people would score between 15 and 25 on this test.
So, the correct answer to the student's question is c) 68%.