2011年9月28日 星期三

[Drama] Wilfred slogan


EP1:Pilot:Happiness
理智和快樂不可能並存
"Sanity and happiness are an impossible combination." by Mark Twain.

EP2:Trust
只相信自己 就不會被背叛
"Trust thyself only, and another shall not betray thee." by Thomas Fuller.

EP3:Fear
恐懼有它的用處 懦弱卻沒有
"Fear has its use, but cowardice has none." by Mahatma Gandhi.

EP4:Acceptance
寬容才會有幸福 -
"Happiness can exist only in acceptance." by George Orwell.

EP5:Respect
想獲得尊重 就要先尊重自己
"Seek respect mainly from thyself, for it comes first from within." by Steven H. Coogler.

EP6:Conscience
良知是條不咬人的狗 但它總是叫個不停
"Conscience is the dog that can't bite, but will never stop barking." Proverb

EP7:Pride
通常傲慢是所有錯誤的根源
"In general, pride is at the bottom of all great mistakes." by Steven H. Coogler.

EP8:Anger
忍氣吞聲並不能讓怒氣平息 只會讓它越發膨脹
"Anger as soon as fed is dead - tis starving makes it fat." by Emiy Dickinson

EP9:Compassion
沒有憐憫之心 就不要對其妄加評論
"Make no judgements where you have no compassion." by Anne McCaffrey

EP10:Isolation
離群索居是事與願違的夢
"Isolation is a self-defeating dream." by Carlos Salinas de Gortari

EP11:Doubt
防人之心不可無 防過了頭反成仇
"Doubt must be no more than vigilance, otherwise it can become dangerous." by George C. Lichtenberg

EP12:Sacrifice
愛就是心甘情願的犧牲
"Love is a willingness to sacrifice." by Michael Novak

EP13:Identity
身份的價值在於它具有目的性
"The value of identity is that so often with it comes purpose." by Richard R. Grant


2011年9月24日 星期六

[Stat]共線性(Collinearity)與交互(Interaction)作用

交互作用

Interaction

共線性

Collinearty

範例

x1x2 y

y=α+β1x1+β2x2+ε

x1x2 y

y=α+β1x1+β2x2+ε

意義

2個變項一同對y作用時,有協同或拮抗現象,若2變項對y存在交互作用時,應該只放入交互作用項,EX: x1x2存在交互作用,則放入迴歸的應為x1*x2,而非x1x2

2變項之間的相關性很高,通常為Pearson's correlation大於0.8時,EX: x1x2有高度相關,表示x1x2y的影響存在共線性,此時只能選x1x2其中一個放入迴歸裡,判定的依據為看哪個變項對y的預測比較重要。

檢查方法

TWO-WAY ANOVA

相關矩陣、CI值、VIFTolerance

結論

所以當迴歸分析要放入變項時,要先檢查變項間的共線性,先解決共線性的問題,再去探討是否有交互作用項的存在。