Develop a relationship to determine the sample
size n for testing the hypothesis H₀:
?² = ?₀² =   15
against H₁: ?² >
?₀². Assume ? = 0.05. It is desired to have ?
= 0.10 if the true value of the variance is 20.  Find the
sample size by trial and error using the
relationship.  Use the calculator available at

http://www.stat.tamu.edu/~west/applets/chisqdemo.html.  Hint:  See
Example 2.13, textbook.