What sources of data are used by demographer

Some demographic data sources are surveys, samples, census measurements, fieldwork, and observation. When using surveys, demographers research through asking questions to select members of the population. When using samples, demographers look at a small portion of the population as a sample group, then apply statistics to the population overall. Census measurements allow demographers to collect data from all residents of a population. Fieldwork is used to conduct studies and surveys out in the population itself (rather than in isolation). Observation is used to monitor and record the behaviors of a population to understand it better.

not sure if this is what you'r looking for nnew= nold

yes

no

blue is scattered more than other colors because it travels as shorter, smaller waves. this is why we see a blue sky most of the time.