Posted by Anonymous on Sunday, October 3, 2010 at 7:07pm.
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. State the appropriate hypotheses to test whether the proportions of defective disks from the two suppliers are the same. At a = 0.05, what can Media Disk conclude? This question is due on day 6.

statistics  MathGuru, Monday, October 4, 2010 at 6:52pm
Try a binomial proportion 2sample ztest using proportions.
Hypotheses:
Ho: pA = pB
Ha: pA does not equal pB >this is a twotailed test (the alternate hypothesis does not show a specific direction).
The formula is:
z = (pA  pB)/√[pq(1/n1 + 1/n2)]
...where n represents the sample sizes, p is (x1 + x2)/(n1 + n2), and q is 1p.
I'll get you started:
p = (73 + 56)/(5000 + 4500) = ? >once you have the fraction, convert to a decimal (decimals are easier to use in the formula).
q = 1  p
pA = 73/5000
pB = 56/4500
Convert all fractions to decimals. Plug those decimal values into the formula and find z. Compare z to the cutoff 0.05 for a twotailed test (cutoff value is z = + or  1.96). If the test statistic you calculated exceeds either the positive or negative cutoff zvalue, reject the null and conclude a difference. If the test statistic does not exceed either the positive or negative cutoff zvalue, do not reject the null (you cannot conclude a difference).
I hope this will help get you started.
Answer This Question
Related Questions
 physics  There are two spinning disks A and B arranged so that they initially ...
 school  Two disks are spinning freely about axes that run through their ...
 math  Numbered disks are placed in a box and one disk is selected at random. ...
 physics  Four items, all with equal masses, are used to construct the device ...
 physics help me  Four items, all with equal masses, are used to construct the ...
 Physics  The figure shows three rotating, uniform disks that are coupled by ...
 Physics please help?????  The figure shows three rotating, uniform disks that ...
 geometry  Samantha has a dog that loves to chase flying disks. To keep her disk...
 geometery  Samantha has a dog that loves to chase flying disks. To keep her ...
 Physics  Two disks are rotating about the same axis. Disk A has a moment of ...
More Related Questions