Last year the records of Dairy Land Inc., a convenience store chain, showed the mean amount spent
by a customer was $30. A sample of 40 transactions this month revealed the mean amount spent was
$33. Assume that the population standard deviation, o, is known and equal to $12. At the 0.05
significance level, can we conclude that the mean amount spent has increased? What is the p-value?
Follow the five-step hypothesis testing procedure.