A wholesaler has recently developed a computerized sales invoicing system. Prior to implementing this system, a manual system was used. The distribution of the number of errors per invoice for the manual system is as follows:

After implementation of the computerized system, a random sample of 500 invoices gives the following error distribution:

a. Show that it is appropriate to carry out a chi-square test using these data.

b. Use the following Excel output to determine whether the error percentages for the computerized system differ from those for the manual system at the .05 level of significance. What do you conclude? 

Transcribed Image Text:

Errors per Invoice Percentage of Invoices 2 3% More Than 3 1% 87% 8% 196 Errors per Invoice Number of Invoices More Than 3 479 10 8