K
Hello,
I'm a student Industrial Engineer Elektromechanics in Belgium. For a thesis I have to make a study about Statistical Process Control.
Recently I've encountered a small problem. Suppose we have an on-line process and every second we get the value of a measurement. We calculate the moving average and plot it on a chart. The problem is which samplesize I have to take. Usually people take a sample size of 2 but is there a formula to calculate the sample size?
I have noticed that in some books the parameters A2, A3, B4, d2,... are just written down for sample sizes from 2 to 25. Do these parameters exist for larger sample size or isn't it useful to use these. In other words, is it still useful for plotting the points on a chart with a sample size of (for example) 28.
greetings,
Kristof N.
I'm a student Industrial Engineer Elektromechanics in Belgium. For a thesis I have to make a study about Statistical Process Control.
Recently I've encountered a small problem. Suppose we have an on-line process and every second we get the value of a measurement. We calculate the moving average and plot it on a chart. The problem is which samplesize I have to take. Usually people take a sample size of 2 but is there a formula to calculate the sample size?
I have noticed that in some books the parameters A2, A3, B4, d2,... are just written down for sample sizes from 2 to 25. Do these parameters exist for larger sample size or isn't it useful to use these. In other words, is it still useful for plotting the points on a chart with a sample size of (for example) 28.
greetings,
Kristof N.