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--- factor_analysis [2018/12/05 12:27] – [Factor solution among many . . .] hkimscil
+++ factor_analysis [2018/12/05 13:13] – [Factor solution among many . . .] hkimscil
@@ Line 298: / Line 298: @@
 > </code>
+<code>> fd <- data.frame(finance,marketing,policy)
+> fd
+  finance marketing policy
+       3         6      5
+       7         3      3
+      10         9      8
+       3         9      7
+      10         6      5</code>
+아래는 population variance, sd를 구하기 위한 function
+<code>> pvar <- function(x) {
++     sum((x - mean(x))**2) / length(x)
++ }
+> psd <- function(x) {
++     sqrt (sum((x - mean(x))**2) / length(x))
++ }</code>
+<code>> fds <- stack(fd)
+> tapply(fds$values, fds$ind, mean)
+  finance marketing    policy
+.6       6.6       5.6
+> tapply(fds$values, fds$ind, pvar)
+  finance marketing    policy
+.84      5.04      3.04
+> options(digits=5)
+> tapply(fds$values, fds$ind, psd)
+  finance marketing    policy
+.1369    2.2450    1.7436
+>
+ </code>
 |  Standardized \\ Variable, \\ Y<sub>i</sub>  |  Observed \\ variance, S<sup>2</sup><sub>i</sub>   |  Loadings on  || Communality, \\ $b^2_{i1} + b^2_{i2} $  |  Percent \\ explained  |  spec. \\ variance  |