7
SSTO = SSRCX , ) t SSECX , ) = SSRCX , ,Xa ) t SSE (Xi , XD ssrcxzlxi ) - SSRCX , ,Xz) - SSRCX , ) SSTO - - SSRCX , ) + SSRCXAIX , )tSSE( Xp , ,Xz ) T T T remainder total variability variability residual after Xi , in Y attributable to variability xn after accounting have X , for X , that is been attributable to accounted Xz for SSTO - - SSRCX , )t SSRCXZIXDTSSRCXslxz.XDTSSECX.kz , Xs ) where SSRCXSIX , , Xz )=SSR( Xs ,Xz , XD - SSRCX , ,Xz )

T variability - GitHub Pages€¦ · Use of Extra Sums of Squares for Testing Hypotheses aboutpk context: Assume we have I, Ii Xp-iwe're assuming Yi = Bot Xik ButEi Ei dN(0,02) *Testing

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Page 1: T variability - GitHub Pages€¦ · Use of Extra Sums of Squares for Testing Hypotheses aboutpk context: Assume we have I, Ii Xp-iwe're assuming Yi = Bot Xik ButEi Ei dN(0,02) *Testing

SSTO = SSRCX , ) t SSECX , )= SSRCX , ,Xa) t SSE (Xi , XD

ssrcxzlxi) -- SSRCX , ,Xz) - SSRCX , )⇒ SSTO -

- SSRCX , ) + SSRCXAIX , )tSSE(Xp , ,Xz)T T T remainder

total variability variability residual after Xi ,in Y attributable to variability xn

after accounting haveX, for X , that is been

attributable to accountedXz for

SSTO -- SSRCX , )t SSRCXZIXDTSSRCXslxz.XDTSSECX.kz , Xs)where SSRCXSIX , ,

Xz)=SSR(Xs ,Xz , XD - SSRCX , ,Xz)

Page 2: T variability - GitHub Pages€¦ · Use of Extra Sums of Squares for Testing Hypotheses aboutpk context: Assume we have I, Ii Xp-iwe're assuming Yi = Bot Xik ButEi Ei dN(0,02) *Testing

Decomposition of SSR into extra sums of squaresGiven Xz

,SSTO = SSR ( XD t SSE ( X1 )

Given Xz as well,SSTO = SSR (XD t SSR (Xzlxse) t

SSECXI,Xa)

SSTO = SSR ( Xs,Xa) t SSE (Xs , XD

= SSR ( Xa ) t SSR (X11 Xs) t SSE ( Xe ,Xz)

Recall. .

. in ANOVA conversations previously ,we talked

about SSTO SSR SSE. . .

but that was inMSTO MSR MSE

the context of simple linear regression

Page 3: T variability - GitHub Pages€¦ · Use of Extra Sums of Squares for Testing Hypotheses aboutpk context: Assume we have I, Ii Xp-iwe're assuming Yi = Bot Xik ButEi Ei dN(0,02) *Testing

In multiple linear regression ,an ANOVA table usually

contains decompositions of the regression sum of

squares into extra sums of squaresYi -- foot §

,pnxikt Ei ,

Ei dN ( o,or)

ANOVA Table for fitting this modelsums of squares Degrade freedom mean squaresSSR ( Xs ,Xs,X3) 3 MSRCX , ,Xz ,XDSSRCX,) I MSRCX , )

Irtysh.ua#tnexfssrcx.m, IfIY£T a Msrcx.milSSRLXI ,XnXd

,model I MSRCXslx.pk/

regression SSR (Xzlxn XDsum of MSECXI ,XqX3)squares SSE ( XI ,Xr , Xs) n - 4

Page 4: T variability - GitHub Pages€¦ · Use of Extra Sums of Squares for Testing Hypotheses aboutpk context: Assume we have I, Ii Xp-iwe're assuming Yi = Bot Xik ButEi Ei dN(0,02) *Testing

Use of Extra Sums of Squares for Testing Hypotheses about pkcontext : Assume we have I , Ii , . . .

. Xp- i , we're assumingYi = Bot Xik But Ei

,EidN( 0,02)

*Testing whether a single pre-

- o

Null,Ho : pre -- O

we already know how

Alternative,Ha : put o ) to do a t - test for this

,

where we compare t*=sYbTzto quantile s of at - distribution with n- p d.f .Consider k =3

Ho corresponds to the redirect model ,Yi -- foot pi Xist for Xist §÷

,Buxiut Ei , Eii NCO ,

02 )

Fit both models or ,make an ANOVA table for the full

model and get SSR Hi , Xs , Xy, . .. and SSE ( Xi,. -

-

, Xp - i )Then we can construct f*=(ssRCX3lXzXziX4i-yXp#)÷fssECx.,X)Under Ho

, Ftt n Fi, n - p n - p

Page 5: T variability - GitHub Pages€¦ · Use of Extra Sums of Squares for Testing Hypotheses aboutpk context: Assume we have I, Ii Xp-iwe're assuming Yi = Bot Xik ButEi Ei dN(0,02) *Testing

Use of Extra Sums of Squares for Testing Hypotheses about piecontext : Assume we have I , Ii , . . .

. Xp- i , we're assumingYi = Bot Xik But Ei

,Ei d NCO

,T2)

*Testing whether a single pre-

- o

Null,Ho : fu = 0

Alternative,Ha : put 0

Com

ssrc*Hxj÷fssEnkIDecicision Rule for a level 2 - test will be :

* If F * E F ( t - d ; I,n - p) conclude Ho

* If F* > FCI- d ; I , n - p) conclude Ha! Ppk 8

p - value given by Pr ( FIFA) , where F - Fi , n -p

Page 6: T variability - GitHub Pages€¦ · Use of Extra Sums of Squares for Testing Hypotheses aboutpk context: Assume we have I, Ii Xp-iwe're assuming Yi = Bot Xik ButEi Ei dN(0,02) *Testing

Use of Extra Sums of Squares for Testing Hypotheses about piecontext : Assume we have I , Ii , . . .

. Xp- i , we're assumingYi = Bot Xik But Ei

,Eid NCO

,T2)

*Testing whether multiple pie , Be e# u are jointly equal to 0Null

,Ho : fu = Be = 0

Alternative,Ha : Puyo or Geto

com

ssrcxu.ie#mmueD:fssEnkIjxP-d/2DecicisionRule for a level 2 - test will be :

* If F * E F ( I - d ; 2 ,n - p) conclude Ho

* If F-*> F ( l- d ; 2 , n - p) conclude Ha

p - value given by Pr ( FIFA) , where F - Fa , n-p

Page 7: T variability - GitHub Pages€¦ · Use of Extra Sums of Squares for Testing Hypotheses aboutpk context: Assume we have I, Ii Xp-iwe're assuming Yi = Bot Xik ButEi Ei dN(0,02) *Testing

Use of Extra Sums of Squares for Testing Hypotheses about

context : Assume we have 4, Ii , . . .

. Xp- i , we're assumingYi = Got Bixiitfszxiztfbzxizt Ei Eid N ( O

,T2)

*Testing whether multiple paz , Bz are jointly equal to 0Null

,Ho : far -- Bss -- O

Alternative,Ha : Pato or B , 40

Com

ssrcx.it#I).fssEnHiihiH/2 4Decicision Rule for a level 2 - test will be :

* If F * E F ( l - d ; 2 ,n - 4) conclude Ho

* If F* > F ( l- Lj 2 , n - 4 , conclude Ha

p - value given by Pr ( FIFA) , where F - Fa , n- y