Answer with explanation:
We know that population is a universe set that represents all individuals related to a required particular characteristic where as a sample is a part of that population represents the whole population.
Given : (a) Based on a randomly selected group of 500 patients with high cholesterol, it was found that 67% have heart disease.
Here, 500 patients are representing a part of population of patients.
Hence, its a sample.
(b) An investigation of 150 randomly selected local restaurants concluded that 42% of local restaurants have serious health code violations.
Here, 150 randomly selected local restaurants are representing a part of population of local restaurants.
Hence, its a sample.
