Answer:
Population is the total number of people that fall into the description of those that the research concerns.
In this case, Population is: Everyone who signed a card saying that they intend to quit smoking.
Sample. This is a subset of the population that the research is based on.
Sample = 1,000 people surveyed.
Parameter and Statistic are both descriptive measures but parameter is for the population and statistic is for the sample.
Parameter = Percentage of total population who have not smoked in 6 months.
Statistic = 21% of sample who have not smoked in 3 months.