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The Sampling Dist
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| Question | Answer |
|---|---|
| In statistics, what is a population? Ex. We are studying the GPA of incoming freshmen at Harvard. What is the population? | the total set of observations that can be made Ex. Ans. The GPAs of all incoming freshmen at Harvard |
| What is a parameter? Ex. We are studying the GPA of incoming freshmen at Harvard. What is the parameter? | a measurable characteristic of a population Ex. Ans. The true mean of the GPAs of all incoming freshmen at Harvard. |
| What is a sample? Ex. We are studying the GPA of incoming freshmen at Harvard. What is a sample? | a set of observations drawn from a population Ex. Ans. A sample would be 40 out of all of the GPAs of all incoming freshmen at Harvard |
| What is a statistic? Ex. We are studying the GPA of incoming freshmen at Harvard. What is a statistic? | a characteristic of a sample. Generally, a statistic is used to estimate the value of a population parameter Ex. Ans. A statistic would be the mean GPA of 40 of the incoming freshmen at Harvard. |
| What is an unbiased estimator? | An unbiased estimator is when the mean of the statistic's sampling distribution is equal to the population's parameter. |
| How do you avoid bias in sampling? | by using random sampling methods |
| How do you reduce variability in sampling? | by increasing the size of the random sample |
| What is the sampling distribution of the statistic? | The distribution of the statistic value in all possible samples of the same size from the same population |