Clarksburg Bakery is trying to predict how many loaves to bake. In the last 100 days, the
bakery has sold between 95 and 140 loaves per day. Here are a histogram and the summary statistics for
the number of loaves sold for the last 100 days.
a) Can you use the normal model to estimate the number of loaves sold on the busiest 10% of all days?
Explain.
b) Explain why you can use these data to construct a 95% confidence interval for the mean number of
loaves sold per day.
c) Calculate a 95% confidence interval and carefully interpret what that confidence interval means.
d) If the bakery would have been satisfied with a confidence interval whose margin of error was twice as
wide, how many days’ data could they have used?
e) When the bakery opened, the owners estimated that they would sell an average of 100 loaves per
day. Does your confidence interval provide strong evidence that this estimate was incorrect? Explain.