====== Week 3 내용 ====== ===== Central Tendency ===== * Central Tendency (집중경향) * Dispersion (variability) -- 분산(변산성) * [[:range]] * [[:outliers]]: It is beyond our scope. Please just refer to it. Won't be appearing in tests. * [[:Variance]] 분산 혹은 변량 * 표본변량 $ s^2 $ * 모집단변량(전집) $ \sigma^2 $ * [[:Standard Deviation]] 표준편차 * Variance calculation formula * {{anchor:variance_calculation_formula}} $ \displaystyle S_x^2 = \displaystyle \frac {\Sigma X^2 - \frac{(\Sigma X)^2}{N} } {N-1} $ * $ \displaystyle \sigma_x^2 = \displaystyle \frac {\Sigma X^2 - \frac{(\Sigma X)^2}{N} } {N} = \displaystyle \frac {\Sigma X^2}{N} - \frac {(\Sigma X)^2}{N^2} = \displaystyle \frac {\Sigma X^2}{N} - \bigg(\frac {\Sigma X}{N}\bigg)^2 = \displaystyle \frac {\Sigma X^2}{N} - \mu^2 $ * [[:Degrees of Freedom]] N-1 * [[:Why n-1]] ===== Sampling Distribution, Standard Error ===== * [[:Sampling]] * [[:Sampling Distribution]] * [[:Central Limit Theorem]] * [[:Standard Error]] ===== CLT에 관한 정리 =====