(New page: <math> H_0:\ \mbox{X has PDF}\ f_{X|\theta}(x|\theta_0)= \begin{cases} 2x & \mbox{for }0 \le x \le 1 \\ ...)
 
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=Question=
 
<math>
 
<math>
 
H_0:\ \mbox{X has PDF}\ f_{X|\theta}(x|\theta_0)=
 
H_0:\ \mbox{X has PDF}\ f_{X|\theta}(x|\theta_0)=
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</math>
 
</math>
  
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Find the ML rule.
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=Answer=
 
To find the ML Rule we say pick  <math>H_1\!</math>  if  <math>f_{X|\theta}(x|\theta_1)>f_{X|\theta}(x|\theta_0)\!</math>
 
To find the ML Rule we say pick  <math>H_1\!</math>  if  <math>f_{X|\theta}(x|\theta_1)>f_{X|\theta}(x|\theta_0)\!</math>
  
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<math> Pr[x\ge1/2|\theta=\theta_1] = \int_{1/2}^{1}1\, dx=1/2\! </math><br><br>
 
<math> Pr[x\ge1/2|\theta=\theta_1] = \int_{1/2}^{1}1\, dx=1/2\! </math><br><br>
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Revision as of 13:46, 22 November 2011


Question

$ H_0:\ \mbox{X has PDF}\ f_{X|\theta}(x|\theta_0)= \begin{cases} 2x & \mbox{for }0 \le x \le 1 \\ 0 & \mbox{else} \end{cases} $


$ H_1:\ \mbox{X has PDF}\ f_{X|\theta}(x|\theta_1)= \begin{cases} 1 & \mbox{for }0 \le x \le 1 \\ 0 & \mbox{else} \end{cases} $

Find the ML rule.

Answer

To find the ML Rule we say pick $ H_1\! $ if $ f_{X|\theta}(x|\theta_1)>f_{X|\theta}(x|\theta_0)\! $


Or in otherwords pick $ H_1\! $ if $ 1>2x\! $ Thus,

$ \mbox{ML Rule: } \begin{cases} \mbox{say }H_1 &\mbox{if }x<1/2 \\ \mbox{say }H_0 &\mbox{else} \end{cases} $

Type I Error: A Type I error is the $ Pr[\mbox{say } H_1|H_0]\! $ this is equivalent to saying $ Pr[x<1/2|\theta=\theta_0]\! $ we calculate this using integration

$ Pr[x<1/2|\theta=\theta_0] = \int_{0}^{1/2}2x\, dx=1/4\! $

Type II Error:A Type II error is the $ Pr[\mbox{say } H_0|H_1]\! $ this is equivalent to saying $ Pr[x\ge1/2|\theta=\theta_1] $ we calculate this using integration

$ Pr[x\ge1/2|\theta=\theta_1] = \int_{1/2}^{1}1\, dx=1/2\! $


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