# Z test for population proportions

Please help with the following problem.

Media Disk, Inc. duplicates over a million 3.5" floppy disks each year by copying masters to stacks of blank disks. The company buys its blank stock from two different suppliers, A and B. The manager has decided to check each supplier's stock by counting the rejected disks in the next run from 5,000 that just arrived from supplier A and 4,500 that just arrived from supplier B. During the run, the disk duplicators rejected 73 of A's disks and 56 of B's.

Media Disk, Inc. duplicates over a million 3.5" floppy disks each year

https://brainmass.com/statistics/z-test/conducting-z-test-for-population-proportions-231204

#### Solution Preview

Please see the attachments.

H0: There is no significant difference in the proportions of defective disks from the two suppliers.

H1: There is significant difference in the proportions of defective disks from the two suppliers.

The test statistic used i:

(see attached file for ...

#### Solution Summary

The solution provides step by step method for the calculation of test statistic and P value . Formula for the calculation and Interpretations of the results are also included.