A professor compares the exam grades of students based on whether they have a learning disability (yes, no) and where they sit in the classroom (in the front, middle, or back row). Different participants were observed in each group. What type of statistical design is appropriate for this study

Gravel is being dumped from a conveyor belt at a rate of 25 ft3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. how fast is the height of the pile increasing when the pile is 14 ft high? (round your answer to two decimal places.) ft/min