Volunteers stop to survey residents at every fourth house from the end of each block in town.
Which is the most appropriate description of this sample?
random sample systematic sample self-selected sample
convenience sample bipartisan sample stratified random sample
The best answer for this is that this sample is a systematic sample.
This is a random sample because everyone in the city, in theory, has a chance to be a part of it. It is not confined to one neighborhood or, as in your previous question, one bus stop. In a systematic sample, what you do is to take every nth unit in your population. That is what you are doing in this sampling technique. You have decided to go to every block and take the 4th house. Therefore, this is a systematic random sample.
This is not a completely random sample because you are not really giving every house an equal chance to be surveyed. If it were a random sample, you would do something like putting every address on a slip of paper in a bag and then picking slips blindly and interviewing the people at that address. This sample is not that random, but it is still somewhat random.
Therefore, the best answer here is that this is a systematic random sample.