Lecture7 Slide - The Department of Statistics and Applied Probability ...
Lecture7 Slide - The Department of Statistics and Applied Probability ...
Lecture7 Slide - The Department of Statistics and Applied Probability ...
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12<br />
Multivariate nonparametric estimation<br />
• Bias <strong>and</strong> variance functions are<br />
{ 1<br />
b α (x) = µ 2 (K)<br />
2<br />
{∫<br />
v(x) = σ 2 (x)f −1 (x)<br />
∂ 2 m<br />
∂ 2 (x) + ∂m (x) ∂f (x) f −1 (x)<br />
x α ∂x α ∂x α<br />
} d<br />
K 2 (u) du<br />
• <strong>The</strong> local linear estimator (to be discussed next) has limiting<br />
distribution <strong>of</strong> the same form, but with<br />
b α (x) = µ 2 (K) 1 2<br />
∂ 2 m<br />
∂ 2 x α<br />
(x)<br />
• <strong>The</strong> local linear weighted least squares problem is<br />
n∑ {<br />
2<br />
{ ˆm (x) , ∇m (x)} = arg min Y i − a − (X i − x) b} T wi (x)<br />
a,b<br />
i=1<br />
}<br />
ST5207 Nonparametric Regression, 10th March 2005