To set up the machine and to create a control chart to be used throughout the run, 15 samples were taken with four resistors in each sample. The complete list of samples and their measured values are as follows: Use three-sigma control limits.

SAMPLE NUMBER READINGS (IN OHMS) READINGS (IN OHMS) READINGS (IN OHMS) READINGS (IN OHMS)
1 1016 995 991 1028
2 1024 981 991 1001
3 990 1015 1025 1012
4 1018 1002 972 995
5 1030 1007 1013 1002
6 1016 1017 985 1002
7 992 1005 1011 1013
8 1028 991 1002 995
9 1030 1014 987 1023
10 986 975 980 988
11 1006 975 1008 1020
12 1016 1004 1020 1019
13 1015 1003 1005 998
14 986 1013 1004 1020
15 981 1014 1015 985

Calculate the mean and range for the above samples.