Draw a simple random sample of two groups of animals from the four groups, and construct a

Question:

Draw a simple random sample of two groups of animals from the four groups, and construct a sample of 20 animals by including all the animals in the sampled groups.

What kind of sample is this?

Exercises 21–24 refer to the population of animals in the following table. The population is divided into four groups:
mammals, birds, reptiles, and fish. image text in transcribed