plugin-Chapter 3 Students

plugin-Chapter 3 Students - What Do Samples Tell Us?...

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CHAPTER 3 What Do Samples Tell Us?
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EXAMPLE 3.1 Gallup conducted a poll from July 2003 to February 2004. They randomly selected 2,527 U.S. adults and asked them, “Would you favor or oppose a constitutional amendment that would define marriage as being between a man and woman?” The result: 1,289 supported the amendment. 51% of the people in the sample supported such an amendment. What percent of all U.S. adults support the amendment? We know the percentage in the sample, we estimate the percentage in the population.
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A parameter is a number that describes the population. A parameter is a fixed number, but we usually don’t know its true value. Examples: True average income of all American families True percentage of all U.S. adults that support an amendment
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A statistic is a number that describes a sample. The value of a statistic is known after collecting
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plugin-Chapter 3 Students - What Do Samples Tell Us?...

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