Canine hip dysplasia is a degenerative disease that causes pain in many dogs. Sometimes advanced warning signs appear in puppies as young as 6 months. A veterinarian checked 47 puppies whose owners brought them to a vaccination clinic, and she found 7 with early hip dysplasia. She considers this group to be a random sample of all puppies. Required:
a. Explain why we cannot use this information to construct a confidence interval for the rate of occurrence of early hip dysplasia among all​ 6-month-old puppies.
b. Interpret a 95% confidence interval for the rate of occurrence of early hip dysplasia among all 6-month-old puppies.