====== Using Statistical Sampling ======
<code>
rnorm(16, 110, 10)
</code>

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A statistical **population** refers to the entire group of things that you're trying to measure, study, or analyze. It can refer to anything from humans to scores to gumballs. The key thing is that a population refers to all of them. A **census** is a study or survey involving the entire population, so in the case of Mighty Gumball, they’re conducting a census of their gumball population by tasting every single one of them. A census can provide you with accurate information about your population, but it’s not always practical. When populations are large or infinite, it's just not possible to include every member.
<WRAP clear/>

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===== How to design a sample =====
Define your target [[:population]]
Define your [[:sampling units]]
  * 책, 단원, 문단, 단어 
  * 개인 (individuals) vs. 지역단위, 구 (동작구 등)
    * 지역단위 범죄율 . . . . 외국인이 많이 사는 곳 . . . . 범죄율이 높을 경우 --> [[:ecological fallacy]]
    * [[:individual fallacy]] or [[:exception fallacy]] 개인을 보고 전체를 판단하는 경우
  * [[:Unit of analysis]] 참조
Define your [[:Sampling#sampling_frame|Sampling Frame]] (표집틀)
If you don’t design your sample well, your sample may not be accurate.
See [[:sampling]] document



===== Sometimes samples can be biased =====
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__Poorly designed questions__

  * Leading question: How great is our hard-working customer service team?
  * Fixed: How would you describe your experience with the customer service team?

  * 유도질문: 매년마다 베스트 서비스 어워드를 받고 있는 저희 호텔에 대해서 어떻게 생각하십니까?
  * 정상질문: 저희 호텔의 서비스에 대해서 평가를 하신다면?

  * 단정질문: 평상시 맥주를 어디에서 즐기십니까?
  * 맥주를 먹는다는 것을 단정하고 질문을 만들었다.

  * 이중장전질문: 저희가게에서 물건을 찾기가 쉽운 편이었으며, 구입하시었나요?

  * Double Negative: 사용하신 물건이 깨끗하지 않지 않았나요?
  * 나는 온라인으로는 드물게 물건을 안산다. 
</WRAP>


===== How to choose your sample(, then) =====
see [[:Sampling]]