Question

How is a random sample obtained?

Name two types of target populations, briefly describe each.

What implications would arise from a low response rate on a survey?

Answer 1

(a) Simple random sampling is the basic sampling techniques where we can select a group of subject ( a sample ) for the strudy from a larger group ( a population ) ,Each individual is chosen entirely by the chance and each members of the population that has an equal chance of being included in the sample . Every possible sample of a given size has the same chance of selection .

(b) A target population consist of the total number of the people or the objects which meets the designated set of the criteria .In other words it is aggregate of all the casses with a certain phenomena about which the reseracher would like to make a generalization For eample ;- a reseracher is interested in identifying the complication of the diabetes mellitus type II among people who have migrated to ludhiana .In this instance , the target population are all the migrants at Ludhiana suffering with diabetes mellitus type II .

In some type s of the research the target population might be as board as all humans , but in other types of research the target population might be as a smaller group like as teenagers , pre-school children .It is looks impossible to study the individual in the target population so the researcher select the single person ( sample ) in the target population as a representative of the target population we are interested in .

(c) Response rates may result in estimates that are biased by selective a non - response As like the example of alcohol consumption in the general population survey . , The response rates for the surveys of the substance use in the general population show a steadily decreasing trend regardless of the mode of the administration ( postal , telephone and face to face ) Studies with the low response rates may produce the prevalence estimates that are biased by selective non- response . That is to be the chance that someone will participate in the survey may be related to the parameter being measured , the survey shown that non- respondents were heavier drinkers than the respodents while others studies shown that the non respondents were often abstainers than the respondents and in some other cases both are heavy drinkers and abstainers were over represented among the non- respondents .