In statistics, a "statistic" refers to a characteristic or measure obtained by using the data values from a sample. It is a summary value that is calculated from a sample of a population, as opposed to a "parameter," which is a characteristic that describes a whole population.
Let's analyze the provided scenarios:
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Thirty students were randomly selected from Mrs. Calzada’s group of 158 students. They were asked how many hours they spend watching TV every day. The mean number of hours was 2.
- This is a statistic based on a sample of the group of students.
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The temperature of every person who walked into a local clinic was recorded. The mean temperature was 98.7° F.
- This is a parameter because it includes every person who walked into the clinic (the entire population).
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All the lions at the local zoo were monitored to see how many hours they slept in a day. The mean number was 4.
- This is also a parameter because it includes all lions at the zoo.
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Every worker at the local arcade was asked how many hours they spend listening to music in a day. The mean number of hours was 5.
- This is a parameter because it describes every worker at the arcade (the entire population of workers).
Based on this analysis, the first scenario is the only example of a statistic, as it is based on a sample of students.