Dr. Ima Gene is trying to develop a drug that will reverse deafness in a breed of dog, the Dalmatian. Many members of this breed have a genetic problem that will cause them to go deaf by the age of one. Dr. Gene is developing a study in which she has found 30 Dalmatians that are about one-year-old and have recently gone deaf. She will give 15 of the dogs the newly developed drug and 15 of them will receive a sugar pill. Dr. Gene finds that after several weeks on the drug, the dogs improve their hearing. Dr. Gene then finds out about the special attention that those dogs were given by her assistant. She decides she needs to repeat her experiment but can only locate 2 dogs in her area that meet her requirements. Why should she wait until she can locate more dogs?