Given: After taking the first exam, 15 of the students dropped the class.
Required: To determine whether the given value is a statistic or a parameter.
Explanation: Parameter and statistic are very similar. The parameter is when the complete data of the population is presented. The statistic is when a particular data is used for fraction of the population.
Since it is given that among all the students in the class 15 students dropped out. Hence the given data is Parameter.
Final Answer: Parameter.