unit root test and structural change. data generating process y=zeros(300,1); u=rndn(300,1); i=2; do...
Post on 20-Dec-2015
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Unit Root Test and Structural Change
Data Generating Process
• Y=zeros(300,1); u=Rndn(300,1);• i=2;• do until i>200;• Y[i,1]=3+0.2*Y[i-1,1]+1*u[i,1];• i=i+1;• endo;
• i=201;• do until i>300;• Y[i,1]=9+0.2*Y[i-1,1]+1*u[i,1];• i=i+1;• endo;
Structural Change-An Example
Unit Root Tests
Unit Root Tests
Unit Root Tests
Low Test Power Problem for Unit Root Test
• Y[i,1]=1*Y[i-1,1]+1*u[i,1]; n=100
• Y[i,1]=0.98*Y[i-1,1]+1*u[i,1]; n=100
• Y[i,1]=0.95*Y[i-1,1]+1*u[i,1]; n=100
• Y[i,1]=0.90*Y[i-1,1]+1*u[i,1]; n=100
• Y[i,1]=0.80*Y[i-1,1]+1*u[i,1]; n=100
Low Test Power Problem for Unit Root Test
Low Test Power Problem for Unit Root Test
Low Test Power Problem for Unit Root Test
Low Test Power Problem for Unit Root Test
Low Test Power Problem for Unit Root Test
Size Distortion Problem
• Y[i,1]=0.90*Y[i-1,1]+1*u[i,1]; n=100
• Y[i,1]=0.90*Y[i-1,1]+1*u[i,1]; n=1,000
Size Distortion Problem