A company manufactures cardboard containers for packaging frozen fruit juices. The manufacturing process forms the containers by joining cardboard stock to a metal bottom. The container can be inspected to determine if there might be leaks along the cardboard seam or where the metal bottom is attached. It is known from long experience that 18% of cans produced by this process are defective. A random sample of 50 cans was selected from the production process on Monday, and it was found that 12% of the selected cans were defective. Because this seemed to indicate an improvement, another sample was selected of the same size on Tuesday, and in it 21% of the cans were defective. The numbers 12%, 18%, and 21% are, respectively, a