2. Over the past five years, the average amount of sales invoices for Swanson Co. is $120. A random sample of 12 sales invoices from this month averaged $112.85 with a standard deviation of $20.80. Conduct test to find out if average sales invoice this month differs from the historical data. Level of significance a = .05
N = 12
M = 112.85
SD = 20.80
Ho: M = 120
Ha: M not equal to 120
Compute standard error of the sample by
SE = ...
The solution uses a hypothesis testing to test the sales level for Swanson Co.