uestion Papers 333 7. (a) Examine the usefulness of index numbers for analysing the data. Discuss various issues that arise in the construction of an index number. In a sample of 800 parts manufactured by a company, number of defective parts was found to be 60. The company, however, claims that only 7% of the product is defective. Apply Z-test to verify whether the manufacture's claim is tenable. (a = 0.05; w = Z, 21.645 of right-tailed test)