sampling
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sampling [2017/03/22 09:16] – [Probability sampling] hkimscil | sampling [2019/03/18 11:58] – [Probability sampling] hkimscil | ||
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==== 원리 | ==== 원리 | ||
* Representativeness (대표성) | * Representativeness (대표성) | ||
- | * ECBS (Equal Chance of Being Selected) | + | * ECoBS (Equal Chance of Being Selected) |
* Sampling bias (샘플링 바이어스) | * Sampling bias (샘플링 바이어스) | ||
* concscious | * concscious | ||
Line 62: | Line 62: | ||
{{IQRandomSample02.jpg}} | {{IQRandomSample02.jpg}} | ||
caption=" | caption=" | ||
- | + | ||
+ | < | ||
+ | |||
+ | var_ <- new.env() | ||
+ | n< | ||
+ | p_mean< | ||
+ | p_sd< | ||
+ | N< | ||
+ | |||
+ | pdf(' | ||
+ | |||
+ | for(i in 1:N) ## do the experiment N times | ||
+ | { | ||
+ | smp< | ||
+ | |||
+ | var_$x_bar< | ||
+ | |||
+ | hist(var_$x_bar, | ||
+ | # Plot a histogram of x_bar values | ||
+ | |||
+ | points(mean(smp), | ||
+ | curve(dnorm(x, | ||
+ | |||
+ | text(2.5, | ||
+ | text(2.5, | ||
+ | |||
+ | curve(dnorm(x, | ||
+ | ## Plot the sample | ||
+ | |||
+ | text(2.5, | ||
+ | text(2.5, | ||
+ | points(smp, | ||
+ | abline(v= mean(smp), | ||
+ | |||
+ | legend(" | ||
+ | lty=c(0, | ||
+ | |||
+ | print(paste(i," | ||
+ | } | ||
+ | dev.off() | ||
+ | </ | ||
+ | {{SE.pdf}} | ||
* Variation See, [[: | * Variation See, [[: |
sampling.txt · Last modified: 2020/12/04 22:37 by hkimscil