Attribute Sample Size

Six Sigma – iSixSigma Forums Old Forums General Attribute Sample Size

Viewing 4 posts - 1 through 4 (of 4 total)
• Author
Posts
• #31145

CAR
Participant

Can someone please explain how to arrive at an appropriate attribute sample size in plain english???
The total population is 1264 accounts. How many accounts are required to obtain a 95% confidence level and a +/- 5% margin of error?
CAR

0
#81917

lin
Participant

It depends on what you want the data to show you. If you are just looking for a sample of the population then 30 would be the number of choice, but if you are trying to detect a change between two sample then you need to know how small the change is. The smaller the change the more samples you will need.

0
#81918

Chip Hewette
Participant

1.  What are you measuring within the 1264 accounts?
2.  What do you want to know about that measurement?  The average value for the measurement from a sample within 1264 accounts?
3.  Do you want to detect a 5 percentage point shift from an average historical value to a ‘new’ value?

0
#81919

abasu
Participant

The formula that you are looking for is
n = Z^2*(p)*(1-p)/(delta p)^2 where
n = sample size
Z = 1.96 for 95% confidence
p = proportion rate (we know total population but not p)
delta p = difference you want to detect (0.1 in this example)

0
Viewing 4 posts - 1 through 4 (of 4 total)

The forum ‘General’ is closed to new topics and replies.