How Creating Equal Groups in random assignment is done?

A randomly selected person has a birthday in April ?

In an experiment, a coin is tossed until the head is observed for the second time. What is the sample space? Can you use set-theoretic expressions to describe the sample space?

A surveyor is determined to sample homeowners in south Philadelphia before the next local election in order to assess key issues that people want to see changes for this year. Suppose the surveyor decides that he will first collect a list of eligible voters from the county, and separate that list into four groups based on annual income. Then, the surveyor randomly assigns each household a number 01-10 within each group of income. The surveyor will select 4 households from each income group using the following random number table. Once 4 households are selected for one group, the surveyor would continue with the next on the same line of the table.   081203 071072 058436 080695 010354 080951 213607 041573 083947 101503 785409   A) What kind of sampling strategy is this? B) Which households would be selected for each income group from this table?