Six samples of n=10 observations have been obtained and the sample means and ranges were computed in minutes:

1. Determine the upper and lower limits for sample mean and range control charts.
2. Is the process in control?

Sample	Mean	Range
1	2.83	0.32
2	3.10	0.4
3	3.08	0.12
4	1.98	0.36
5	3.03	0.46
6	2.07	0.45

Hint: