Following is the probability distribution for age of a student at a certain public high school. X
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P(x) 0.09 0.22 0.24 0.28 0.15 0.02

(a) Find the variance of the ages. Round the answer to at least four decimal places.
The variance of the ages is

The american academy of pediatrics wants to conduct a survey of recently graduated family practitioners to assess why they did not choose pediatrics for their specialization. provide a definition of the population, suggest a sampling frame, and indicate the appropriate sampling unit.