Tagged: sample size
Hello, I am having some trouble with the Six Sigma Greenbelt certification exam, and I was wondering if I could get some help. I have a few questions that are stomping me.
Question 1: Should USL and LSL be excluded from control charts and do they confuse operators ( assuming they operate within specification limits but the process may not necessarily be controlled)?
Question 2: CLT (Central limit theory) – Would you say its the route or risk taken when we assume that when the sample is 30 and above, the sample reflects the population mean approaches normality. The question is ROUTE vs RISK??
A company has a policy of no longer than 40min to get to work.
Employees drive to work: Mean = 39mins SD=7mins
A sample (70 Employees) was conducted to see how long it would be for employees taking the metro to work.
The results of the sample test: Mean = 34mins SD=21mins
Do the employees have a higher probability of getting to work faster by car or metro?
Would decreasing the SD by 6 help employees arrive on time by car?
Should the company adjust the policy to accommodate for employees coming from different distances?
Question 4: Would we consider linearity as errors within several individual samples?
Damola – Although the iSixSigma audience is willing to help, they do not want to do someone’s work for them.
How do you think the problems can/should be solved?
If you think you’re doing something wrong, why do you think that?
The more details you provide, the more likely you are to get a response.
I am having trouble question found on a sample exam too.
Need to know fewest samples for 99% confidence that when sheep are fed a a new diet, the avg weight gain is 5 lbs over current avg of 20 lbs. weight gain per sheep is normally dist. with a SD of 4.3 lbs. I know the formula is n=(Zsq x st dev sq)/(E)sq
Therefore I came up with Z=2.58 SD=4.3 E=5 plugged them in and came up with 4.19 which of course means I went horribly wrong as the answer is 101.
Where is the flaw in my calculation?