http://commres.net/ 2026-04-12T08:37:26+00:00 http://commres.net/ http://commres.net/_media/wiki/logo.png text/html 2026-04-12T06:38:01+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/t-test_summary?rev=1775975881&do=diff t-test sum up rm(list=ls()) rnorm2 <- function(n,mean,sd){ mean+sd*scale(rnorm(n)) } ss <- function(x) { sum((x-mean(x))^2) } z.test <- function(sam, mu, sigma) { diff <-mean(sam) - mu se <- sigma / sqrt(length(sam)) z.cal <- diff / se p.val <- pnorm(abs(z.cal), lower.tail = F)*2 two <- abs(qnorm(.05/2)) return(cat( " z value:", round(z.cal,5), '\n', "p value:", round(p.val,8), '\n', "diff: ", mean(sam), "-", mu, "=", mean(sam)-mu, '\n', "se: ", se, '\n', … text/html 2026-04-12T06:37:58+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/?image=pasted%3A20260412-063758.png&ns=pasted&rev=1775975878&tab_details=history&media_do=diff&do=media <img src="http://commres.net/_media/pasted/20260412-063758.png?w=500&amp;h=500&amp;tok=03434d" alt="20260412-063758.png" loading="lazy" width="500" height="500" /> text/html 2026-04-12T06:37:39+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/?image=pasted%3A20260412-063739.png&ns=pasted&rev=1775975859&tab_details=history&media_do=diff&do=media <img src="http://commres.net/_media/pasted/20260412-063739.png?w=500&amp;h=500&amp;tok=824c77" alt="20260412-063739.png" loading="lazy" width="500" height="500" /> text/html 2026-04-12T06:37:22+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/?image=pasted%3A20260412-063722.png&ns=pasted&rev=1775975842&tab_details=history&media_do=diff&do=media <img src="http://commres.net/_media/pasted/20260412-063722.png?w=500&amp;h=500&amp;tok=4660a9" alt="20260412-063722.png" loading="lazy" width="500" height="500" /> text/html 2026-04-12T06:37:09+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/?image=pasted%3A20260412-063709.png&ns=pasted&rev=1775975829&tab_details=history&media_do=diff&do=media <img src="http://commres.net/_media/pasted/20260412-063709.png?w=500&amp;h=500&amp;tok=9ae098" alt="20260412-063709.png" loading="lazy" width="500" height="500" /> text/html 2026-04-12T06:36:52+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/?image=pasted%3A20260412-063652.png&ns=pasted&rev=1775975812&tab_details=history&media_do=diff&do=media <img src="http://commres.net/_media/pasted/20260412-063652.png?w=500&amp;h=500&amp;tok=f28c9e" alt="20260412-063652.png" loading="lazy" width="500" height="500" /> text/html 2026-04-12T06:36:36+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/?image=pasted%3A20260412-063636.png&ns=pasted&rev=1775975796&tab_details=history&media_do=diff&do=media <img src="http://commres.net/_media/pasted/20260412-063636.png?w=500&amp;h=500&amp;tok=07bc79" alt="20260412-063636.png" loading="lazy" width="500" height="500" /> text/html 2026-04-12T06:36:08+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/?image=pasted%3A20260412-063608.png&ns=pasted&rev=1775975768&tab_details=history&media_do=diff&do=media <img src="http://commres.net/_media/pasted/20260412-063608.png?w=500&amp;h=500&amp;tok=4d8146" alt="20260412-063608.png" loading="lazy" width="500" height="500" /> text/html 2026-04-12T06:35:49+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/?image=pasted%3A20260412-063549.png&ns=pasted&rev=1775975749&tab_details=history&media_do=diff&do=media <img src="http://commres.net/_media/pasted/20260412-063549.png?w=500&amp;h=500&amp;tok=26ac9b" alt="20260412-063549.png" loading="lazy" width="500" height="500" /> text/html 2026-04-12T06:35:31+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/?image=pasted%3A20260412-063531.png&ns=pasted&rev=1775975731&tab_details=history&media_do=diff&do=media <img src="http://commres.net/_media/pasted/20260412-063531.png?w=500&amp;h=500&amp;tok=7e6fdd" alt="20260412-063531.png" loading="lazy" width="500" height="500" /> text/html 2026-04-12T04:17:00+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/c/mrm/2026/schedule?rev=1775967420&do=diff 이전 페이지 ---- exploring media theories * Week 01: March 2, 5 * Week 02: March 9, 12 * Week 03: March 16, 19 * Week 04: March 23, 26 (the 1st quiz) ---- choosing media theories * Week 05: March 30, April 2 * Week 06: April 6, 9 ---- developing and revising hypotheses text/html 2026-04-07T23:02:31+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/r/two_sample_t-test?rev=1775602951&do=diff Independent sample t-test 의 standard error 값을 구하는 방법이 얼른 머리에 들어오지 않으면, see mean and variance of the sample mean: 샘플평균들의 집합이 가지는 평균과 분산 (CLT) sa statistical review: 분산의 계산 두 샘플을 취해서 평균을 구한 후 (mean of A, mean of B), 그 차이를 기록하는 것을 무한히 하여 그 분포를 구하는 것은 아래와 같이 정리, 이해할 수 있다. \begin{eqnarray} E \left[ \overline{X} - \overline{Y} \right] & = & E \left[ \overline{X} \right] - E \left[ \overline{Y} \right] & = & {\mu_{X}} - {\mu_{Y}} \\ V \left[ \overline{X} - \overline{Y} \right] & = & V \left[ \overli… text/html 2026-04-07T23:00:52+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/c/ms/2026/lecture_note_week_05?rev=1775602852&do=diff 모집단의 평균과 표준편차를 알고 있을 때 독립변인의 효과를 알고 싶을 때, 혹은 모집단의 성격이 참인지 거짓인지 알고 싶을 때 One sample z-test t-test 꼭 읽을 것 Distribution of Sample Means -- mu = 40, sigma = 4 (hence var = 16) 인 모집단에서 n = n 사이즈의 샘플링을 무한 반복할 때 그 샘플평균들이 모인 집합 $ \frac {\text{obtained difference}} {\text{se}} = \frac {\text{difference due to the IV}} {\text{random error}} $\begin{eqnarray} z\;\;\;\text{or}\;\;\;t & = & \frac{\overline{X}-\mu}{\sigma_{\overline{X}} }, \quad \text{where } \;\; \sigma_{\overline{X}} = \frac{\sigma}{\sqrt{n… text/html 2026-04-07T22:39:53+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/two_sample_t-test?rev=1775601593&do=diff Two sample t-test Independent sample t-test, two sample t-test Difference of Two means Hypothesis test 등 같은 의미 Theory 가정 * 두 모집단 p1, p2 가 있다 * 각 집단에서 샘플을 취해서 그 평균을 구한 후 * 그 차이를 기록한다. \begin{eqnarray*} \overline{X} & \sim & \left( \mu, \;\; \frac{\sigma^2}{n} \right) \\ & & \text{in other words, } \\ E \left[ \overline{X} \right] & = & \mu \\ Var \left[ \overline{X} \right] & = & \frac{\sigma^2}{n} \\ & & \text {Assuming that X1 and X2 are independent } \\ \overline{X_{1}} & \sim & \l… text/html 2026-04-07T22:30:39+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/mean_and_variance_of_the_sample_mean?rev=1775601039&do=diff Mean and variance of sample mean 전제: Expected value (기대값)와 Variance (분산)의 연산에 과한 법칙으로는 참조. X,Y are Independent variables. \begin{eqnarray*} E[aX] &=& a E[X] \\ E[X+Y] &=& E[X] + E[Y] \\ Var[aX] &=& a^{\tiny{2}} Var[X] \\ Var[X+Y] &=& Var[X] + Var[Y] \\ Var[X-Y] &=& Var[X] + Var[Y] \end{eqnarray*} Mean of the sample mean 평균이 (mean) $\mu$ 이고, 분산이 (variance) $\sigma^{2}$ 인 모집단에서 (population) 독립적으로 추출되어 관찰되는 $X_{1}, X_{2}, . . . , X_{n}$$X_1$\begin{eqnarray*} X_{1}, X_{2}, X_{3}, . . . , X_… text/html 2026-04-06T14:53:30+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/c/ms/2026/schedule?rev=1775487210&do=diff 통계에 대한 기초적인 이해 가설과 가설검증 * 가설의 종류와 그 종류에 따른 통계분석법 * z-test * t-test * ANOVA * Factorial ANOVA * correlation * regression * multiple regression * factor analysis text/html 2026-04-06T13:45:40+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/c/ms/2026/schedule/week06_t-test_and_anova_note?rev=1775483140&do=diff see anova note text/html 2026-04-06T03:13:53+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/c/mrm/2026/schedule/building_hypotheses?rev=1775445233&do=diff Research Idea: * How relating other influencers affect users' experiences? * search results * How relating other influencers affect users' experience of youtube viewing * search results * watching influencers' content and users' behavior change * search results * The effect of social media influencers' on teenagers Behavior: an empirical study using cognitive map technique * not a good example of building hypotheses text/html 2026-04-05T23:57:44+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/?image=r%3Apasted%3A20260405-235744.png&ns=r%3Apasted&rev=1775433464&tab_details=history&media_do=diff&do=media <img src="http://commres.net/_media/r/pasted/20260405-235744.png?w=500&amp;h=500&amp;tok=7358e9" alt="20260405-235744.png" loading="lazy" width="500" height="500" /> text/html 2026-04-05T23:57:33+00:00 hkimscil (hkimscil@undisclosed.example.com) http://commres.net/?image=r%3Apasted%3A20260405-235733.png&ns=r%3Apasted&rev=1775433453&tab_details=history&media_do=diff&do=media <img src="http://commres.net/_media/r/pasted/20260405-235733.png?w=500&amp;h=500&amp;tok=5e1eed" alt="20260405-235733.png" loading="lazy" width="500" height="500" />