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Asymptotic Methods in Statistical Inference - Statistics Centre

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26<br />

• Related example: Let{ } =1<br />

be a sample from<br />

ad.f. with density . We wish to estimate the<br />

quantile = −1 () ( 6= 0 1). Assume<br />

( ) 0. Then is strictly <strong>in</strong>creas<strong>in</strong>g at <br />

and ( )=. If (1) ≤ (2) ≤ ≤ () are<br />

the order statistics, then a possible estimate of<br />

is ( ) ,where ( ) has ≈ observations<br />

smaller than or equal to it. Formally, we require<br />

<br />

= + (−12 )<br />

This is satisfied if = [], s<strong>in</strong>ce then<br />

| − | ≤ 1. Put<br />

We have<br />

= <br />

= √ ³ ( ) − ´<br />

<br />

( ≤ ) =<br />

Ã<br />

Ã<br />

( ) ≤ +<br />

!<br />

the number of obsn’s<br />

+ √ <br />

<br />

is ≤ − <br />

= ( ≤ − ) <br />

µ<br />

where ∼ =1− <br />

√ <br />

!<br />

<br />

µ<br />

+ √ <br />

. Note<br />

that, by the Mean Value Theorem (details <strong>in</strong> the

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