Answer: Choice D
To calculate a point estimate, we need to know the sample size.
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Explanation:
Let's go through the answer choices.
- A) False. A sample statistic could equal to the population parameter. It won't always happen, but it might happen sometimes (in rare cases).
- B) False. Point estimates are only defined for populations. They estimate a population parameter. For example, the sample mean xbar is a point estimate of the population mean (mu).
- C) False. In practice, we will hardly know anything about the population. This includes the population size. The goal of statistics is to measure population parameters by using sample statistics as estimation methods.
- D) True. We can easily calculate the sample size because it is relatively much smaller compared to the population. Plus, when selecting the sample, the sample size is often pre-determined to some set number. The sample size will help us determine things like the sample mean and the sample proportion.
