Will has eight puppies. he is concerned his puppies may be infected with parvo, a disease that is deadly in young dogs unless diagnosed and treated early. the cost of the test to determine if the dog has parvo is $59. will cannot afford to have all of his puppies tested. the veterinarian has suggested that will reach into the pen where the dogs stay and pick up the first one that walks into his hand. (if one dog tests positive, then will can assume that all the puppies are infected. if the puppy is not infected, then will can assume that his puppies are healthy.) what kind of a sampling technique is the vet suggesting will use?