A researcher wants to develop a product for families who have small children. He needs to determine if there is a nationwide interest in a toy that will help children describe their emotions. He asks only a sample of the population to complete his survey. What should be true of the sample so that the results of the survey can be used to predict the results of surveying the population?
The size of the sample should be the same size as the population.
The families included in the sample should represent the families in the population.
The families included in the sample cannot be included in the population.
The size of the sample should be larger than the size of the population.