Records in a three-county area show that in the last few years, Girl Scouts
sell an average of \(47.93\) boxes of cookies per year, with a population
standard deviation of \(8.45\) boxes per year. Fifty randomly selected Girl
Scouts from the region sold an average of \(46.54\) boxes this year. Scout
leaders are concerned that the demand for Girl Scout cookies may have
decreased.
a. Test at the \(10 \%\) significance level whether the average number of boxes
of cookies sold by all Girl Scouts in the three-county area is lower than the
historical average.
b. What will your decision be in part a if the probability of a Type I error
is zero? Explain.