Members of a polling organization survey 600 of the 6,342 registered voters in a town randomly choosing names from a list of all registered voters. is their sample likely to be representative

Yes, it is a large enough sample to be considered representative.

Whenever you are using a sample to learn about an entire population, you are never 100% sure that your sample is representative. However, we can make predictions based on the sample size.

In the case of having a sample size of 600 in a population of 6342, we can be fairly confident that we are representative. We are withing a margin of error of 5% at the 95% confidence level.