A political scientist surveys 34 of the current 147 representatives in a state’s legislature.
What is the size of the sample:
What is the size of the population:

The size of the sample is 34 representatives, as this is the number of individuals surveyed by the political scientist. They selected these representatives from a larger group, which forms the basis of their research.

The size of the population is 147 representatives, representing all the current members in the state’s legislature. This total group is what the political scientist is trying to understand better through the survey of the smaller sample.