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SOLUTION TO EXERCISE 1
(a) Using Poisson statistics, the margin of error is the square root of the number of data points. So if the m.o.e. is 5%, then the total number of data points is X, where sqrt(X) = 0.05 * X and the answer is X = 400. (b) A short list of the many possible factors include: -- The people sampled do not represent a fair sample of the population; gender, political bias, ethnicity, economic status, geography, age, etc. -- The question asked may have been unclear or worded to elicit one answer preferentially, by accident or design. -- Respondents may have felt pressured to pick a particular answer, for whatever reason. -- Respondents who were asked to participate in the poll but refused may not have been taken into account properly. -- Respondents may not have seen the entire debate, or may have observed the debate differently, for example on TV, on radio, or in the live audience. |