Problem: Three suppliers provide parts in shipments of 500 units. Random samples of six shipments from each of the three suppliers were carefully checked and the numbers of parts not conforming to standards were recorded. These numbers are listed in the following table.
Supplier A Supplier B Supplier C 28 22 33 37 27 29 34 29 39 29 20 33 31 18 37 33 30 38
Required:
a. Calculate the between-groups, within-groups and total sum of squares.
b. Complete the analysis of variance table and test the null hypothesis that the population mean number of parts per shipments not conforming to standards are the same for all three suppliers.