In statistics, a population is a set of similar items or events which is of interest for some question or experiment and a sample is a set of data collected from a population by a defined procedure. In the following examples of statistical studies, identify the population of interest and the sample and provide the sample size.
  1. In a study of the relationship between socio-economic class and unethical behavior, a group of five students from a local community college were asked to identify themselves as having low or high social-class by comparing themselves to others with the most (least) money, most (least) education, and most (least) respected jobs. They were also presented with a jar of individually wrapped chocolate candies and informed that the candies were for children in a nearby laboratory, but that they could take some if they wanted. After completing some unrelated tasks, participants reported the number of candies they had taken. It was found that those who were identified as upper-class took more candy than others.
    • Population:
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  2. The Buteyko method is a shallow breathing technique developed by Konstantin Buteyko, a Russian doctor, in 1952. Anecdotal evidence suggests that the Buteyko method can reduce asthma symptoms and improve quality of life. In a scientific study to determine the effectiveness of this method, researchers recruited two hundred asthma patients aged 18-69 who relied on medication for asthma treatment. These patients were split into two research groups: one practiced the Buteyko method and the other did not. Patients were scored on quality of life, activity, asthma symptoms, and medication reduction on a scale from 0 to 10. On average, 32% participants in the Buteyko group experienced a significant reduction in asthma symptoms and an improvement in quality of life.
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    • Sample size:
  3. The 2010 General Social Survey asked the question, "After an average work day, about how many hours do you have to relax or pursue activities that you enjoy?" to a random sample of seven thousand Californians. The average relaxing time was found to be 1.6 hours.
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    • Sample size: