6. A researcher is studying how many hours per day people are staying at home during the COVID-19 pandemic. Suppose he obtains a list of all residential addresses in a town and then randomly selects 100 of these. He goes door-to-door during the day and knocks or rings the doorbell. If someone answers the door, he asks them to estimate how many hours per day they have been home during the past week. If no one answers the door, he moves on to the next house on the list. He then averages all the numbers obtained to try to estimate the average time at home in the whole town.

(a) The researcher took a random sample of households. Are the people he talks to like a random sample of all the people in the town? Considering specifically the variable he is interested in studying, in what way are the people he talks to likely to be different from the townspeople in general?

(b) Will the researcher's average tend to be too high, too low, or about right? Explain your answer.