LSSGB: Variable control chart subgroup sizes are generally 3, 4, 5, or 6 for all of the following reasons EXCEPT:
OPTIONS
- They are large enough so that averages of data will follow the normal distribution
- They fit onto traditional chart paper very well
- Larger sizes permit an opportunity for process changes within the subgroup
- They permit a separation of within time from time-to-time variation
ANSWER
They fit onto traditional chart paper very well
EXPLANATION
Please note that a negative response is requested. The weakest selection is option b. Control chart paper was developed to support a logical control chart sample size. Sample sizes should not be chosen to fit a handy form. The other items have merit.
