Use the previous information to answer the following questions about the shark survey.
a. Describe in words the parameter of interest.
b. Identify the numeric value of the statistic corresponding to the above parameter.

A zoologist at a large metropolitan zoo is concerned about a potential new disease present among the 243 sharks living in the large aquarium at the zoo. The zoologist takes a random sample of 15 sharks from the aquarium, temporarily removes the sharks from the tank, and tests them for the disease. He finds that 3 of the sharks have the disease.