1. May 5, 2009 #1

   superwolf

   

   If the average number of raisins in a randomly chosen bun is 9 with a variance of 9, how many buns must be tested if a test with a significance level of 0.05 with 90% probability is gonna reveal than the number of raisins is less than 10?
   
   ATTEMPT:
   
   [tex]
   n = \frac{(z_{\alpha} + z_{\beta})^2 \sigma^2}{\delta^2} = \frac{(1.645+1.28)^2 \cdot 9}{1^2} = 77.0006[/tex]
   
   So, at least 78 buns.
   
   Correct answer. At least 82 buns.
   
   What's wrong?

    

   superwolf, May 5, 2009
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3. May 5, 2009 #2

   Mark44

   

   Insights Author

   Staff: Mentor

   Help us out here. What test are you using? It looks vaguely like something to do with the F statistic, but I don't have my statistics references with me. What do z_alpha and z_beta represent, and how did you get them?

    

   Mark44, May 5, 2009

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